Cro WatchesSeiko 7S26-0040
Seiko SKX diver 200 m (Submariner style), late 1990s-2010s. What it is, how to date it, how to check it's original, and what it's worth.
The Seiko 7S26-0040 is a Seiko SKX diver 200 m (Submariner style) (SKX031, SKX033). It runs on Seiko's calibre 7S26, an automatic movement with 21 jewels, beating 21,600 times an hour. It can't be wound with the crown and winds itself as you wear it, and the seconds hand keeps running while you set the time. Seiko made the 7S26 from about 1996 to 2019.
How old is it? The first digit of the serial number on the caseback is the last digit of the year, the second is the month (1–9, then O, N, D). On a 7S26, made 1996–2019, a serial starting 15 means May 2001 or 2011. Our Seiko Identifier works it out for you.
Is it original? The small dial code at 6 o'clock should start with 7S26, like the caseback. If it starts with another number, the dial was made for a different model (a replacement dial).
Specifications
| Movement | Calibre 7S26, automatic |
|---|---|
| Jewels | 21 |
| Beat rate | 21,600 per hour |
| Hand-winding | no |
| Hacking seconds | no |
| Power reserve | about 41 hours |
| Calendar | day-date |
| Made | about 1996–2019 |
| Known as | SKX031, SKX033 |
Have a 7S26-0040? Check yours in seconds: open the Seiko Identifier with 7S26-0040 filled in.
Questions
Can I wind a Seiko 7S26-0040 by hand?
No. The 7S26 winds itself as you wear it. To start it, move the watch gently from side to side for 20–30 seconds.
How do I set the day and date on a Seiko 7S26-0040?
Most 7S26 watches either change the day when you press the crown, or have a quickset when you pull the crown out one click. Never change the date between 9 pm and 1 am. Step by step: crowatches.com/seiko-set-day-date.html
How old is my Seiko 7S26-0040?
Read the serial on the caseback: the first digit is the last digit of the year, the second the month. The 7S26 was made about 1996–2019, which fixes the decade.