Omega Serial Numbers & Reference Numbers: The Definitive Guide

Before you can truly understand an Omega watch, you need to speak its language, and that language is written in numbers. Every Omega carries two key identifiers: a serial number that traces its production history, and a reference number that reveals exactly what it is.

This guide will walk you through both, breaking down decades of evolving systems to help you identify clear and accurate information about an Omega watch.

Contents

Omega Serial Numbers

• Omega Serial Number Date Chart: Non-Speedmaster Models
• Omega Serial Number Date Chart: Speedmaster Models
• Omega Serial Number Date Chart: Speedmaster Models

Omega Reference Numbers

• Early Omega 4-5 Digit References (Pre-1962)
• Omega 6-7 Digit MAPICS References (1962 - 2007)
• Omega 8 Digit PIC References (1988 - 2007)
• Omega PIC14 References (2007 - Present)

Omega Serial Numbers

Serial numbers are the breadcrumbs that lead back through Omega's history. Sometimes they line up perfectly with a production year; other times they reveal quirks in how Omega built and shipped its watches. In this section, we'll explore how to find an Omega serial number, and what those digits can (and can't) tell you.

What Is an Omega Serial Number?

An Omega serial number is a unique 7 or 8-digit identifier etched onto each watch. Originally located on the movement, more recent models also feature this number on the caseback or lugs. These numbers allow you to date the production of a watch, identify its authenticity, and sometimes track its service history.

Omega serial numbers are generally sequential, but discrepancies may occur due to how movements and cases are assembled and stocked.

The Omega Speedmaster uses a different reference number system than other models, so if you're looking to find information about a Speedmaster watch, such as the year of production, it's important to use the correct data.

Where to Find Omega Serial Numbers

Depending on the watch's era and model, serial numbers may be located:

• On the movement (commonly for vintage models)
• On the interior caseback
• On the exterior caseback
• On the back of the lugs (common from 1990s onward)
• On official paperwork: warranty card, COSC certificate, Extract from the Archives

Some models with ETA-based or non-COSC movements may lack movement serials but still have external ones.

Omega Serial Number Date Chart: Non-Speedmaster Models

This reference chart enables you to estimate the production year of an Omega watch based on the serial number:

Omega Serial Number Date Chart: Speedmaster Models

For Speedmaster watches, the reference chart below should be used instead of the general Omega chart above to estimate the production year.

Why Are Speedmaster Serial Numbers Different?

The Omega Speedmaster is one of the most iconic watches in the world, and perhaps famous for being the first watch worn on the moon in 1969. Because of its NASA association and highly collectible variants, Speedmasters are more closely tracked and studied than most other Omega collections.

Unlike other Omegas, Speedmasters often:

• Came from specialised or segregated production batches
• Were used in NASA testing, military contracts, and commemorative editions
• Were sometimes produced ahead of commercial release

These factors mean Speedmaster serials don't always follow the same linear pattern seen in Omega's general chart. While many Speedmasters use serial ranges also seen in other models such as the Seamaster or De Ville, the way those ranges map to years can differ slightly.

For example, Speedmaster serial numbers in the 14,000,000 range correspond to production around 1957, whereas for other models this number range corresponds to production around 1954. This highlights how Speedmasters often had different timing for movement engraving, assembly, and delivery.

Understanding the Limitations of Omega Serial Numbers

While serial numbers are widely used by collectors and professionals to estimate the production year of an Omega watch, it's important to understand that this information is made up of approximations and not absolute records.

There are several reasons for this:

1. Lack of Official Year-by-Year Publication

Omega has never released a fully detailed, publicly available serial number timeline by year. As a result, most charts are compiled from a mix of archival extracts, watch service data, and observed production patterns. This means there may be inconsistencies or gaps, especially in less-documented periods such as the mid-1970s or late 1980s.

2. Movement vs. Watch Assembly Date

Serial numbers are typically applied to the movement during production. However, the movement may not be cased into a watch (and subsequently sold), for months or even years. Therefore, a watch could contain a movement produced in one year but be assembled and shipped in another. This difference can lead to confusion when attempting to determine the precise manufacturing year.

3. Stock Rotation and Overlap

In some cases, earlier movements remained in inventory and were cased after newer ones. This means a lower serial number doesn't always indicate an earlier completed watch. Overlapping batches can occur, particularly during periods of high production or when transitioning between calibers or case designs.

4. Estimated, Not Exact

Even the most detailed charts should be used as guides rather than rigid rules. While they can typically narrow a production date down to a 1-2 year range, there may be outliers.

For many years, Omega offered a service called the “Extract from the Archives”, which provided historical production details about individual watches based on their serial numbers. However, as of 2023, this service has been officially discontinued. For additional help in verifying a specific watch's production year, it is recommended to seek an evaluation from a specialist such as Watches.co.uk.

Omega Reference Numbers

If serial numbers tell you when your watch was made, reference numbers tell you what it is. They capture everything from the case material to the dial colour, bracelet type, and even special edition status. But the way Omega has written these codes has changed a lot over the years. Here, we'll decode the major systems, from the early case-only codes to the detailed 14-digit PIC numbers used today.

What Is an Omega Reference Number?

An Omega reference number (or PIC number) is a unique alphanumeric code assigned to every Omega watch model. It encodes a wide range of information, including:

• Model family (e.g. Speedmaster, Seamaster)
• Case and bracelet materials
• Movement and complications
• Dial color and design
• Size, generation, and more

Where to Find the Omega Reference Number

Vintage Omega watches: Stamped inside the caseback (you'll need to open the case)

Modern Omega watches: Often not visible externally, but can be found on:

• Warranty card
• Hangtag
• Sales receipt

Always compare the reference number on paper with one decoded via PIC logic. Inconsistencies could signal aftermarket alterations or non-original parts.

Evolution of Omega Reference Number Systems

Over the years, Omega has used several different formats for its references from simple early codes to modern Product Identification Code (PIC) systems.

Early Numeric Reference System (Pre-1962)

Before 1962, Omega used simple numeric reference numbers, usually in the format XXXX or XY XXXX.

These numbers were typically stamped inside the caseback and used to identify case styles and model families. There was no consistent encoding of movement type, dial, or complications, making these references limited in utility for model comparison today.

MAPICS System (1962 - 2007)

Introduced around 1962, the MAPICS system brought a more structured classification format to Omega's internal operations.

There were two main versions of the MAPICS reference format:

• 6-digit format: XY.123.456 (common during the 1960s)
• 7-digit format: XY.123.4567 (phased in from the 1970s onward)

These codes encode information about case shape, movement type, features, and design, although Omega never released an official key for full decoding. That said, many collector communities have partially reconstructed the logic behind them.

Although eventually phased out from commercial use, MAPICS remained active internally until around 2007.

PIC System: Short Format (1988 - 2007)

Introduced in 1988, the PIC system stands for Product Identification Code and was created to support Omega's growing international retail and catalog system.

This system was used for consumer-facing materials such as warranty cards, catalogs, hangtags, and invoices.

• Format: ABCC.DE.FF

PIC System: Long Format (2007 - Present)

In 2007, Omega upgraded the PIC system to a 14-digit reference format to accommodate more technical and stylistic variations.

• Format: AAA.BB.CC.DD.EE.FF

This is the system still in use today and is visible in Omega's online catalog and product literature.

Now that we've taken a look at how Omega's reference system has evolved over the years, let's examine each system in more detail to understand what they can tell us about a watch.

Early Omega 4-5 Digit References (Pre-1962)

Before 1962, Omega used a simple reference system, usually in one of the following formats:

• XXXX
• XXXX-X
• XY XXXX

How To Read Early Omega References

During this period, Omega's referencing system was not as formally structured or consistent as later systems, and therefore it cannot be used to gain as much accurate information about watches from the era.

In fact, Omega has acknowledged that some of these early reference numbers were primarily internal case designations, not necessarily full model references. This means they don't typically provide information about the movement, dial or bracelet/strap.

Many references however did include a two digit material code:

• CK or MI: Steel
• OT or OJ: Solid gold
• KO: Gold cap
• PK: Gold filled

Other parts of the reference included a base reference (XXXX) which indicates the primary case design, and sometimes a suffix (-X) which denotes a specific iteration or variation of the base model.

For example, if we consider reference CK 2915-1 (the first Speedmaster), the reference indicates that this is a steel case watch and the first iteration of the model.

If we consider another reference, CK 2915-3, we can see this is also a steel cased watch, of the same model, but the third iteration. Changes could include things such as bezel material or hand style, for example.

Before long, Omega needed more than just simple case numbers to keep track of its expanding line-up, and in the early 1960s it introduced a whole new system with the aim of bringing greater clarity and standardisation to its references.

Omega 6-7 Digit MAPICS References (1962 - 2007)

In 1962 Omega introduced the MAPICS system. This was the brand's first attempt at standardising reference numbers for complete watch configurations, moving beyond the simpler case-only references used previously.

Before MAPICS, reference numbers were largely case-maker codes and varied in format. MAPICS gave Omega a consistent internal language for identifying watches in production, service, and parts ordering.

This system remained in place until around 2007, covering the vast majority of Omega's mechanical and quartz production over four decades. It was used internally for manufacturing, cataloguing, and servicing, but also appeared on some casebacks, service documents, and sales records. There were two main formats:

• 6-digit MAPICS: AA.BBB.CD (common from 1962 to around 1970)
• 7-digit MAPICS: AA.BBB.CDD (phased in during the 1970s and dominant thereafter)

You will often see them written without dots (e.g., 145022), but in Omega records, the dot separators were standard.

How To Read Omega 6-7 Digit MAPICS References

Although Omega never published an official decoding key, collector research and service documentation suggest the structure followed a loose hierarchy:

Reference: AA.BBB.CD(D)

Now that we've seen how the MAPICS references are structured, let's look more closely at each section of the number to see how to decode them.

Case Material

AA.BBB.CD(D)

The first part of the reference typically indicates the material used to make the case of the watch.

11-14 - Stainless steel

15-19 - Gold-cap / gold-filled steel

20-29 - Solid gold (yellow, rose, white)

30-39 - Steel + other metal

50-59 - Gold + other material

60-69 - Precious metal (platinum, palladium)

90-99 - Other materials (titanium, ceramic - late MAPICS years)

Movement Type & Functional Category

AA.BBB.CD(D)

The next part of this reference format typically denotes the movement type and functional category of the watch.

135 - Manual-wind, time only

136 - Manual-wind with date

145 - Manual-wind chronograph

146 - Manual-wind chronograph, alternative spec

165 - Automatic, no date

166 - Automatic with date

167 - Automatic GMT

168 - Automatic chronometer, no chronograph

169 - Automatic chronometer with day-date

176 - Automatic chronograph, 12-hour counter

178 - Automatic chronograph (later generation)

183 - Quartz, time only

186 - Quartz chronograph

196 - Automatic with date, dress configuration

This does not strictly correspond to specific model families (e.g. Speedmaster), although certain categories were often dominated by one line and used exclusively within this line for several decades.

For example, 145 would overwhelmingly indicate the watch was a Speedmaster from this period. However, rather than 145 corresponding exactly to a Speedmaster, it's more accurate to say 145 denotes a manual wind chronograph (which would include the Speedmaster). But 145 could also indicate another manual Omega chronograph from the same era.

Case Shape / Construction

AA.BBB.CD(D)

The third segment of the reference was typically a single digit and denoted the case shape of the watch, together with the general type of case construction.

0 - Round, screw-back

1 - Round, monocoque (front-loading)

2 - C-shaped case

3 - Tonneau

4 - Square / rectangular

5 - Cushion case

Dial Variant

The final position in the MAPICS style reference (or final two positions in later versions) indicated the specific dial variant, and sometimes bezel or handset differences too.

Early MAPICS (single digit: 0-9)

0 - Base dial variant

1 - Alternate markers (e.g. Roman, Arabic)

2 - Alternate dial colour

3 - Special finish (e.g. linen, sunburst)

4 - Precious stone markers (e.g. diamond, onyx)

5-9 - Other variations (usage varied)

Transition from 6 to 7 Digits

The shift to 7-digit MAPICS in the early 1970s gave Omega more flexibility, and allowed for far more combinations as its catalogue expanded. This could include:

• Dial colour and finish
• Hand shape and/or colour
• Style of indices
• Logo style (applied vs printed)
• Bezel insert type (tachymeter, telemeter, countdown, etc.)
• Lume type (tritium, Luminova)

However, it's important to be aware that some meanings are model specific. For example, a “10” on one reference might be a silver dial, but on another it could be a blue sunburst, each with a specific style of hands or indices.

Why MAPICS Can Be Tricky to Decode

References from this period can sometimes be a bit challenging to understand. There are a few reasons for this:

1. Internal focus: These references were not designed for consumer marketing. They were intended for internal use by Omega, so meanings were functional, not descriptive, and not officially shared.
2. Evolving logic: Some codes changed meaning as calibres and case designs evolved.
3. Reuse: Middle block codes could be reused decades later for unrelated watches.
4. Overlap: The same movement category could appear in multiple lines (e.g., 145.xxxx could be a Speedmaster or another manual chronograph).

By the late '80s, Omega's catalogues and sales materials needed a friendlier, more retail-ready code. The brand came up with a new PIC system that ran alongside MAPICS for nearly 20 years.

Omega 8 Digit PIC References (1988 - 2007)

In 1988, Omega introduced a consumer-facing Product Identification Code (PIC) to standardise how models were listed on hangtags, warranty cards and in catalogues. Each set of digits in an 8-digit PIC tells part of the story: from the watch's family to its dial, bracelet, and sometimes even the market it was destined for.

How To Read Omega 8 Digit PIC References

Often referred to as the “short PIC”, it used an eight-digit structure, commonly written as:

ABCC.DE.FF

Here's a quick summary of what each part of the reference indicates:

Let's explore how to decode each of these parts in more detail:

Product Family

ABCC.DE.FF

The first digit in an Omega short PIC reference indicates the product family that the watch belongs to.

1 - Constellation

2 - Seamaster

3 - Speedmaster

4 - De Ville

5 - Louis Brandt

6 - Reserved for Internal Use

7 - De Ville Vasarelli / special De Ville series

Case and Bracelet Material

ABCC.DE.FF

The second number in an 8-digit Omega reference indicates the material/s that the case and bracelet are made from:

1 - Gold case / gold bracelet

2 - Steel & gold case / steel & gold bracelet

3 - Steel & gold case / partial steel & gold bracelet

4 - Steel & gold case / steel bracelet

5 - Steel case / steel bracelet

6 - Gold case / strap

7 - Steel & gold case / strap

8 - Steel case / strap

9 - Other materials (e.g. titanium, ceramic)

Variation Code

ABCC.DE.FF

The next part of the reference is a two-digit segment that represents the variation code. This is the specific variant of the watch, which can include slight or minor differences. It's important to be aware that these codes are model specific, for example a “90” in a Speedmaster reference is not the same as a “90” in a Seamaster reference.

00-99 - Model-Specific Variation

Dial Colour

ABCC.DE.FF

This part of the 8-digit Omega reference is used to indicate the dial colour.

1 - Champagne

2 - White

3 - Silver

4 - Grey

5 - Black

6 - Ivory

7 - Mother of Pearl

8 - Blue

9 - Special colours / other

Hour Markers

ABCC.DE.FF

This part of the reference number denotes the style of hour markers that the watch uses.

0 - Mixed (lume plots + applied markers, combo layouts)

1 - Indexes (batons)

2 - Arabic numerals (full or partial)

3 - Roman numerals

4 - Mixed with precious stones (factory diamond/hour stone sets with mixed indexes)

5 - Diamonds (full or partial diamond-set markers)

6-9 - Reserved for special editions or factory custom orders

Strap or Bracelet Style

ABCC.DE.FF

The final portion of the 8-digit Omega PIC reference is a double digit code that denotes the style of strap or bracelet supplied with the watch.

00 - Bracelet (default)

01 - Black strap (leather, rubber, NATO)

02 - Brown strap (leather)

03 - Blue strap (leather/rubber)

04 - Green strap (special editions)

05 - Burgundy strap (rare, some Constellations)

06 - White strap (often ladies' models)

07 - Cream/beige strap (rare)

08 - Yellow strap (very rare)

09 - Red strap (rare)

31 - Black alligator + deployant clasp (factory set)

32 - Brown alligator + deployant clasp (factory set)

33 - Blue alligator + deployant clasp (rare)

34 - Green alligator + deployant clasp (special editions)

39 - Special strap set (limited editions)

40>+ - Other internal codes for exotic materials, clasp variants, or regional packaging.

Omega 8-Digit PIC Reference Examples

Let's take a look at some examples of putting this reference system into practice:

Example 1: Reference 3590.50.00

Breaking the reference down into our individual segments gives us:

A B CC. D E. FF

3 5 90. 5 0. 00

• A (3) = Speedmaster
• B (5) = Steel case / steel bracelet
• CC (90) = Moonwatch variation
• D (5) = Black dial
• E (0) = Mixed markers
• FF (00) = Bracelet

Result: Speedmaster Professional Moonwatch, Cal. 861/1861, hesalite, black dial, bracelet.

Breaking the reference down into our individual segments gives us:

A B CC. D E. FF

2 5 31. 8 0. 00

• A (2) = Seamaster
• B (5) = Steel case / steel bracelet
• CC (31) = Diver 300M auto “Bond”
• D (8) = Blue dial
• E (0) = Mixed markers
• FF (00) = Bracelet

Result: Seamaster Diver 300M Automatic “Bond”, blue dial, bracelet (Cal. 1120).

MAPICS and 8-Digit PIC Used in Parallel (1988-2007)

When Omega introduced the 8-digit PIC system in 1988, it didn't immediately replace the older 6- or 7-digit MAPICS system. Instead, both systems ran side-by-side for almost two decades.

MAPICS was an internal manufacturing and service code:

• It was often stamped inside casebacks and primarily used for production tracking and parts ordering.
• It was used in Omega's factory, service centres, and technical documentation.

PIC was a consumer-facing product code:

• It was typically printed on hangtags, warranty cards, catalogues, and price lists.
• This was easier for retailers and customers to use in sales materials.

This meant that a single watch could have two different reference numbers:

• MAPICS code inside the caseback (e.g., 145.022 for a Speedmaster Pro)
• PIC code on the warranty card (e.g., 3590.50.00)

Why did Omega use MAPICS & PIC at the Same Time?

These two referencing systems served different purposes, so Omega used them concurrently. The MAPICS code was often the “mechanical fingerprint” for servicing, meaning watchmakers could order the right case, dial, or movement parts using it.

Meanwhile the PIC code was used to identify the sales package (the product a consumer would receive), including case material, dial colour, strap/bracelet, and sometimes market-specific details.

When the PIC system was introduced, MAPICS was already deeply embedded in Omega's internal systems and spare parts catalogues. Many case designs and calibres had been in production for decades under MAPICS, so retiring it would have required rewriting service manuals for every model. For long-lived models like the Speedmaster Professional, both codes were kept in use until the 2007 switch to the 14-digit PIC system.

Omega PIC14 References (2007 - Present)

By 2007, Omega's range had grown so diverse that even the 8-digit PIC couldn't capture all the variations. The solution was the 14-digit PIC14 system. This is a detailed, standardised code that records everything from case size to movement type, dial material, and sequence number.

It's the most granular system Omega has ever used, and once you know how to read it, you can identify a watch's exact configuration at a glance.

How To Read 14 Digit Omega PIC14 References

The current Omega reference system is a 14 digit code, usually in the following format:

AAA.BB.CC.DD.EE.FFF

Here's a key to understand what each part of the reference means:

Let's take a closer look into each section of the reference and the specific codes within each one.

Family & Model

AAA.BB.CC.DD.EE.FFF

The first three digits in the PIC denote the Omega model family and individual model of the watch.

1XX - Constellation

References beginning with a 1 denote that the watch is part of the Constellation family. Here are the codes for each model:

121 - Constellation Double Eagle

123 - Constellation (Men's)

127 - Constellation (Ladies')

128 - Constellation Petite Seconde / Ladies Automatic

129 - Constellation Quartz (Modern)

130 - Constellation Globemaster

131 - Constellation Manhattan

132 - Constellation Manhattan Quartz (Men's)

2XX - Seamaster

References beginning with a 2 denote that the watch is part of the Seamaster family. Here are the codes for each model:

210 - Seamaster Diver 300M (Modern)

212 - Seamaster Diver 300M (Classic)

213 - Seamaster Diver 300M Chronograph

215 - Seamaster Planet Ocean 600M

220 - Seamaster Aqua Terra

221 - Seamaster Aqua Terra Chronograph

222 - Seamaster Aqua Terra Annual Calendar

223 - Seamaster Aqua Terra Ladies

224 - Seamaster Aqua Terra GMT / Worldtimer

225 - Seamaster Aqua Terra Small Seconds

228 - Seamaster Aqua Terra Ultra Light

229 - Seamaster Aqua Terra Shades

233 - Seamaster 300

234 - Seamaster 300 Heritage

235 - Seamaster Railmaster

236 - Seamaster 300 GMT / Big Triangle

237 - Seamaster Ploprof 1200M

238 - Seamaster Chronostop / Vintage Tributes

240 - Seamaster Edizione Venezia

3XX - Speedmaster

References beginning with a 3 denote that the watch is part of the Speedmaster family. Here are the codes for each model:

304 - Speedmaster Moonphase Co-Axial

310 - Speedmaster Professional (2021-present)

311 - Speedmaster Professional (Pre-2021), Dark Side of the Moon / Ceramic, First Omega in Space

324 - Speedmaster 38mm

327 - Speedmaster Mark II

329 - Speedmaster Racing, some 2022 Speedmaster '57 models

331 - Speedmaster '57 (Pre-2022)

332 - Speedmaster '57 (2022-Present)

334 - Speedmaster Chronoscope

336 - Speedmaster Chronoscope in Bronze/Gold

4XX - De Ville

References beginning with a 4 denote that the watch is part of the De Ville family. Here are the codes for each model:

424 - De Ville Prestige (Men's)

425 - De Ville Ladymatic

428 - De Ville Trésor Quartz

429 - De Ville Trésor Quartz (Updated)

430 - De Ville Trésor Master Chronometer (Men's Auto)

431 - De Ville Trésor Small Seconds / Power Reserve

432 - De Ville Hour Vision

434 - De Ville Prestige (Updated generation)

435 - De Ville Trésor Manual Wind (Men's)

436 - De Ville Tourbillon Master Chronometer

5XX - Special & Numbered Editions

References beginning with a 5 denote that the watch is a special, limited, or numbered edition. Most special editions are part of an existing model family outlined above, however Omega treats these differently within its reference system.

513 - De Ville Central Tourbillon

514 - Museum Collection

515 - Central Tourbillon (Precious Metal Editions)

516 - Numbered Editions / Collectors Series

522 - Olympic Games Collection

526 - Yachting / Regatta Chronographs

529 - Speedmaster Limited Editions / Anniversary Models

578 - Special & Commemorative Editions (non-Speedmaster)

Example: 434.53.41.21.02.001
In this example we can see the family and model code is 434, indicating a De Ville Prestige (Updated generation)

Case & Bracelet/Strap Material

AAA.BB.CC.DD.EE.FFF

After the family and model, the next part of the Omega 14-digit reference is used to identify the material used for the watch case and the bracelet or strap that it is sold with. The first digit typically applies to the case, with the second digit representing the bracelet or strap. Here's what each of these means:

1X - Steel Case

When this part of the reference begins with 1, it usually means that the case is made from steel.

10 - Steel case, steel bracelet

11 - Steel case, other metal bracelet

12 - Steel case, non-metal strap (leather, fabric, or rubber)

13 - Steel case, non-metal strap (CITES/exotic)

15 - Paved steel case, steel bracelet

16 - Paved steel case, other metal bracelet

17 - Paved steel case, non-metal strap (leather, fabric, or rubber)

18 - Paved steel case, non-metal strap (CITES/exotic)

2X - Steel & Gold Case

Material codes beginning with 2 indicate that the watch case is a combination of steel and gold.

20 - Steel and gold case, steel and gold bracelet

21 - Steel and gold case, other metal bracelet

22 - Steel and gold case, non-metal strap (leather, fabric, or rubber)

23 - Steel and gold case, non-metal strap (CITES/exotic)

25 - Paved steel and gold case, steel and gold bracelet

26 - Paved steel and gold case, other metal bracelet

27 - Paved steel and gold case, non-metal strap (leather, fabric, or rubber)

28 - Paved steel and gold case, non-metal strap (CITES/exotic)

3X - Steel & Other Material

Material codes beginning with 3 indicate that the case is made from a combination of steel and another material such as ceramic or titanium (not gold).

30 - Steel and other material case, steel and other material bracelet

31 - Steel and other material case, other metal bracelet

32 - Steel and other material case and non-metal strap (leather, fabric, or rubber)

33 - Steel and other material case and non-metal strap (CITES/exotic)

35 - Paved steel and other material case, steel and other material bracelet

36 - Paved steel and other material case, other metal bracelet

37 - Paved steel and other material case, non-metal strap (leather, fabric, or rubber)

38 - Paved steel and other material case, non-metal strap (CITES/exotic)

5X - Gold Case

Material codes beginning with 5 indicate a gold case (one of several types of gold used by Omega).

50 - Gold case, gold bracelet

51 - Gold case , other metal bracelet

52 - Gold case, non-metal strap (leather, fabric, or rubber)

53 - Gold case, non-metal strap (CITES/exotic)

55 - Paved gold case, gold bracelet

56 - Paved gold case, other metal bracelet

57 - Paved gold case, non-metal strap (leather, fabric, or rubber)

58 - Paved gold case, non-metal strap (CITES/exotic)

6X - Gold & Other Material

Watches in this series typically have a case made from a combination of gold and another material such as ceramic (not steel).

60 - Gold and other material case, gold and/or other material bracelet

61 - Gold and other material case, other metal bracelet

62 - Gold and other material case, non-metal strap (leather, fabric, or rubber)

63 - Gold and other material case, non-metal strap (CITES/exotic)

65 - Paved gold and other material case, gold and/or other material bracelet

66 - Paved gold and other material case, other metal bracelet

67 - Paved gold and other material case, non-metal strap (leather, fabric, or rubber)

68 - Paved gold and other material case, non-metal strap (CITES/exotic)

9X - Other Material

References with a material code that begins with 9 indicate that the case is made from a material other than steel or gold, such as ceramic, titanium, or bronze.

90 - Other material case, other material bracelet (same as case)

91 - Other material case, metal bracelet

92 - Other material case, non-metal strap (leather, fabric, or rubber)

93 - Other material case, non-metal strap (CITES/exotic)

95 - Paved other material case, other material bracelet (same as case)

96 - Paved other material case, metal bracelet

97 - Paved other material case, non-metal strap (leather, fabric, or rubber)

98 - Paved other material case, non-metal strap (CITES/exotic)

Example: 434.53.41.21.02.001
In our example we can see the material code is 53, indicating a gold case and non-metal alligator strap.

Types of Gold Used in Omega Watches

Omega uses a variety of proprietary and traditional gold alloys in its watches. These are not differentiated within the 14-digit reference system, but here are the main types of gold you'll encounter in modern Omega watches.

• Yellow Gold: A classic 18K gold alloy that offers a traditional rich yellow tone. The composition is 75% gold with silver and copper.
• Sedna Gold: Omega's proprietary rose gold alloy named after Sedna, a trans-Neptunian object known for its reddish tone. This gold has a warm pink hue and is composed of 75% gold (18K), with copper and palladium.
• Canopus Gold: Omega's proprietary white gold alloy named after the star Canopus, the second brightest star in the sky. The colour is bright white with a subtle sheen and it's composed of 18K gold alloy with platinum, rhodium, and palladium
• Moonshine Gold: A pale, Omega proprietary yellow gold developed for durability. It has a softer tone than traditional yellow gold and is composed of 18K gold with silver, copper, and palladium.
• Bronze Gold: A unique bronze-gold hybrid alloy that's used in some Seamaster 300 Heritage models. It has a deep bronze tone with warm gold accents and is composed of 37.5% gold (9K), plus bronze, silver, and palladium.

CITES / Exotic Straps

Straps marked as CITES refer to materials regulated under the Convention on International Trade in Endangered Species of Wild Fauna and Flora, such as alligator or lizard. If a watch has a strap made from a CITES-regulated material, it may require special documentation for international shipping or resale. It could also be subject to import/export restrictions in certain countries. Omega labels these references separately to help identify watches with non-metal straps that include CITES-regulated leather, so retailers and customs agents can flag them properly

Case Diameter

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The next part of the Omega reference number indicates the diameter of the case. The number shows the size in millimeters across the full width.

13 - 13 mm

16 - 16 mm

19 - 19 mm

22 - 22 mm

24 - 24 mm

25 - 25 mm

26 - 26 mm

27 - 27 mm

28 - 28 mm

29 - 29 mm

30 - 30 mm

31 - 31 mm

32 - 32 mm

33 - 33 mm

34 - 34 mm

35 - 35 mm

36 - 36 mm

37 - 37 mm

38 - 38 mm

39 - 39 mm

40 - 40 mm

41 - 41 mm

42 - 42 mm

43 - 43 mm

44 - 44 mm

45 - 45 mm

46 - 46 mm

47 - 47 mm

48 - 48 mm

Example: 434.53.41.21.02.001
In our example, the case size value shows that the watch has a diameter of 41mm

Movement & Complications

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This part of the reference indicates the type of movement used inside the watch, and the complications that it includes.

The first digit indicates the type of movement. A mechanical movement can be either automatic or manual-winding.

The second digit indicates the number of complications. Complications refer to features beyond hours, minutes, and seconds. However, chronograph functionality is not counted as a complication for the second digit, as this is indicated by the first digit.

Movement Type (first digit):

0 - Mechanical

1 - Mechanical Chronometer

2 - Mechanical with Co-Axial

3 - Mechanical Chronograph

4 - Mechanical Chronograph Chronometer

5 - Mechanical Chronograph with Co-Axial

6 - Quartz

7 - Quartz Chronograph

Number of Complications (second digit):

0 - No complications

1 - 1 complication

2 - 2 complications

3 - 3 complications

4 - 4 complications

5 - 5 complications

6 - 6 complications

7 - 7 complications

8 - 8 complications

9 - 9 complications

Example: 434.53.41.21.02.001
In our example, the movement and complication code is 21, which means the watch has a mechanical Co-Axial movement with one complication.

Dial Colour & Material

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The penultimate part of the 14-digit Omega reference indicates the colour of the dial, as well as whether the dial includes any precious stones or is made from a special material. For most watches, the reference does not indicate the dial material. Most dials are made from painted or painted brass, however some are made from precious metals or ceramic.

01 - Black

02 - Silver

03 - Blue

04 - White

05 - White mother-of-pearl (MOP)

06 - Grey

07 - Colored mother-of-pearl (e.g., pink, blue)

08 - Champagne

09 - Ivory

10 - Other color

11 - Red

12 - Yellow

13 - Brown

51 - Black with precious stones

52 - Silver with precious stones

53 - Blue with precious stones

54 - White with precious stones

55 - White mother-of-pearl with precious stones

56 - Grey with precious stones

57 - Colored mother-of-pearl with precious stones

58 - Champagne with precious stones

59 - Ivory with precious stones

60 - Other color with precious stones

61 - Red with precious stones

62 - Yellow with precious stones

63 - Brown with precious stones

64 - Sapphire-set dial

99 - Fully paved or special materials dial

Example: 434.53.41.21.02.001
Our example watch has a dial code of 02, indicating that it has a silver dial (without any precious stones).

Sequence Number

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The final three digits of the Omega 14-digit reference number are assigned sequentially by Omega to differentiate between watches that share the same specifications in the first five segments of the 14-digit reference.

This sequence number shows the iteration or variation of that specific reference, as updates are introduced. This helps to identify variations such as different straps, dials, casebacks, packaging or special editions. The number itself does not reveal production year or quantity.

Example: 434.53.41.21.02.001
Our example watch has a dial code of 02, indicating that it has a silver dial (without any precious stones).

Serial & Reference Numbers: Omega's Hidden Language

From simple four-digit case codes to today's 14-digit PIC references, Omega's numbering systems have always been a quiet language, written into every watch, and the keys to understanding the brand's history.

Understanding what they mean helps to unlock the details of when a piece was made, what it was built from, and how it was originally configured. These codes can confirm authenticity, narrow down production dates, and sometimes point to rare or unusual variations that set a watch apart.

While the systems have changed over time, the principle stays the same: every number tells part of the story. Whether you're a seasoned collector, or simply curious about the Omega on your wrist, understanding this hidden language turns each reference and serial number into a window into the brand's history.

If you need any further assistance in identifying your Omega, or are looking to purchase a pre-owned model, here at Watches.co.uk we can help. Our experts have decades of experience dealing in Omegas, from vintage rarities to the latest models. Browse our current stock of Omega watches online, or contact us for more information.