Seiko Serial Numbers Complete Guide and Date

Seiko Serial Numbers Complete Guide and Date

What is a serial number on a Seiko? Where is the serial number on a Seiko, and how can you use it to date your watch? These are common questions that we get from our readers.

To help you identify the year of your Seiko, and to understand when it was made, we have compiled a complete Guide to Seiko watches serial numbers. Dig in!

Background to Seiko serial numbers

The vast majority of timepieces feature a serial number. This is especially true for luxury watches and mechanical watches that are made not only as a means of telling the time but also to appreciate.

With that said, all Seiko watches are equipped with a serial number.

The serial number has a number of different purposes. Most important, it helps the manufacturer keep track of each and every single watch they produce. But at the same time, the recorded databases of the serial numbers are rarely shared with the public, but used and kept by the company alone. This also includes Seiko.

Seiko watches are equipped with several different numbers.

Seiko case back number

The numbers on a Seiko can be found on the case back. There, you will find a number that actually refers to two different numbers – the case code and the caliber (movement).

The number on the Seiko case back consists of one number, a hyphen, and then an additional number. Both of these consist of four digits. These are not the serial number.

The serial number contains six digits and can also be found on the case back. Each Seiko watch has a serial number that is unique to that exact watch.

Furthermore, the case back of a Seiko watch reveals a bunch of different information. This includes the date of manufacturing, the movement type, case material, the maker, how to open the caseback, and more. In some cases, part of, or all, this information, is indicated on the inside of the case back, which means you need to open it in order to access it.

Note: This article is for informational purposes only. To the best of our knowledge, it is correct, but typos or mistakes may exist.

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How to date your Seiko watch with the serial number

The good thing is that you can use the serial number of your Seiko to date it in order to know when it was produced.

The format for dating it via the serial number is as follows:

The first digit in the number will indicate the last digit of the year the watch as manufactured. The second digit indicates the month, and the last 4 digits the production number, which is unique to the watch.

Seiko started with the six-digit serial numbers in 1966, which means you will not be able to use the below methods to date your watch. Prior to this, Seiko used seven digits. Note that during this time, there was a transition period where both systems were used.

This means that when the first digit indicates:

  • 1: The year of manufacture ends with 1
  • 2: The year of manufacture ends with 2
  • 3: The year of manufacture ends with 3
  • 4: The year of manufacture ends with 4
  • 5: The year of manufacture ends with 5
  • 6: The year of manufacture ends with 6
  • 7: The year of manufacture ends with 7
  • 8: The year of manufacture ends with 8
  • 9: The year of manufacture ends with 9

Worth noting is that the month (second digit) is indicated as 1-9 for January to September. 0 is October, N is November, and D is December. As seen below:

  • 1: January
  • 2: February
  • 3: March
  • 4: April
  • 5: May
  • 6: June
  • 7: July
  • 8: August
  • 9: September
  • 0: October
  • N: November
  • D: December

With that said, this information does not tell us the decade of which the watch mas manufactured. This is a bit trickier, but possible. In order to know when your watch was made, you need to know in which period that the watch was released. Ways you can do this is research the model but also the caliber number. This is helpful as most Seiko calibers (movements) are not in production for more than a decade. Those often have small visual differences that allow you to know if it is an early movement or a late movement.

It also helps to research the model itself to know when it was released and when it was discontinued.

The last four digits of the Seiko serial number tend to be a bit more tricky to read. Generally, the last four digits indicate the production number of the watch. For example, 5000 indicates that it is the 5000th watch from that model. There are exceptions to this rule, however.

Lastly, there are also helpful Seiko serial number decoders online that you can use. To decode your Seiko with these tools, are you need to do is enter your serial number and movement number.

52 thoughts on “Seiko Serial Numbers Complete Guide and Date

  1. I couldn’t resist commenting. Very well written.

    1. Hamre pas hi old model wach siryal no hi 476334 7009

  2. This article explain clearly what the number stands for behind a Seiko watch. Easy to understand.

  3. This morning I discovered that I own two Seiko 7A38’s (exact same model 7A38-713A SAA104J) produced in August 1987 with IDENTICAL case-back serial numbers. Both are stamped 783736.

    1. Hello mate, I have one which was belong to my dad. The serial number is 511496. So the first digit which is 5, shows the production year, but ‘65? ‘75 or ‘85? Can you help me please?

      1. Search for Seiko serial number decoder. You write in the serial number and movement number (four digits before -). I found out my father’s to be made in december 1984.

      2. That is exactly what I’m asking giving me the last number of the year it was produced doesn’t help me identify the exact year mine is a one so was it 71-81 -91- 2001?


  5. Seiko. 5. Serial number. 611452

  6. Would someone help to solving this numbers.

  7. Want to know how much is my seiko worth .serial563121

    1. Hi,
      For appraisals, please refer to this page:

      Kind regards,
      Millenary Watches

  8. I have a seahorse watch but it only has a 7 digit code on it, it does not have any other codes. I know my mum got it for my dad in the early 70’s. Help

  9. I bought my Seiko new at a store in San Diego in either 1983 or 1984. Now I know that my 135339 was made in March of (likely) 1981. Thank you!

    1. Glad you found this guide helpful!

      Kind regards,
      Millenary Watches

  10. 100135

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