Seiko SJE101
Ref. SJE101 · In production
- Case39.5 mm
- Thick12.3 mm
- Lug-to-lug47.2 mm
- Water res.200 m
- MovementAutomatic
- CrystalSapphire
Overview
The Seiko SJE101 is a diver watch from the Prospex collection, part of the Marinemaster family. It has a 39.5 mm stainless steel case, 12.3 mm thick, 47.2 mm from lug to lug. Inside is a automatic movement (calibre 6L37) with 45 h of power reserve. You also get 200 m water resistance, a sapphire crystal and a bracelet.
Who it suits
- Wrists of roughly 15.9–17.7 cm (6.3–7.0 in), by our Watch Finder sizing guide
- Swimming, snorkelling and diving
- People who enjoy seeing a mechanical movement at work
Strengths
- Sapphire crystal resists scratches
- Certified to the ISO 6425 diver's standard (200 m)
- Screw-down crown helps keep water out
- Display caseback shows the movement
- Hacks and hand-winds, so it is easy to set
Written by Watch.co from the published specs below. These are not owner reviews.
Full specifications
Case
| Case diameter | 39.5 mm | seikowatches.com · 23 Oct 2026 |
|---|---|---|
| Thickness | 12.3 mm | seikowatches.com · 23 Oct 2026 |
| Lug-to-lug | 47.2 mm | seikowatches.com · 23 Oct 2026 |
| Case material | Stainless steel | seikowatches.com · 23 Oct 2026 |
| Crystal | Sapphire | seikowatches.com · 23 Oct 2026 |
| Anti-reflective coating | Anti-reflective coating on inner surface | seikowatches.com · 23 Oct 2026 |
| Caseback | Display (see-through) | seikowatches.com · 23 Oct 2026 |
| Bezel | Unidirectional rotating | seikowatches.com · 23 Oct 2026 |
| Water resistance | 200 m | seikowatches.com · 23 Oct 2026 |
| Screw-down crown | Yes | seikowatches.com · 23 Oct 2026 |
| ISO 6425 diver | Yes | seikowatches.com · 23 Oct 2026 |
| Magnetic resistance | 4,800 A/m | seikowatches.com · 23 Oct 2026 |
| Weight | 155 g | seikowatches.com · 23 Oct 2026 |
Dial
| Luminous material | LumiBrite | seikowatches.com · 23 Oct 2026 |
|---|---|---|
| Date | Date | our classification |
Movement
| Movement type | Automatic | seikowatches.com · 23 Oct 2026 |
|---|---|---|
| Calibre | 6L37 | seikowatches.com · 23 Oct 2026 |
| Made in-house | Yes | seikowatches.com · 23 Oct 2026 |
| Power reserve | 45 h | seikowatches.com · 23 Oct 2026 |
| Hacking seconds | Yes | seikowatches.com · 23 Oct 2026 |
| Hand-winding | Yes | seikowatches.com · 23 Oct 2026 |
Strap / Bracelet
| Bracelet / strap | Bracelet | seikowatches.com · 23 Oct 2026 |
|---|---|---|
| Lug width | 20 mm | seikowatches.com · 23 Oct 2026 |
Other
| US list price (MSRP) | $2,800 | seikowatches.com · 23 Oct 2026 |
|---|---|---|
| Production status | In production | seikowatches.com · 23 Oct 2026 |
| Style (our classification) | Diver | our classification |
Specs are summarised in our own words from the brand's product page. Each row links its source and the date we checked it. Fields we haven't verified are left out rather than guessed.
Variants with the same specs
Same case, movement and bracelet or strap; typically a different dial or finish.
More in Marinemaster
Similar alternatives
Picked with Watch Finder's style tags and sizing.
Questions about the Seiko SJE101
How big is the Seiko SJE101?
The case is 39.5 mm wide, 12.3 mm thick and 47.2 mm from lug to lug.
What movement does the Seiko SJE101 use?
It uses the 6L37 calibre, a automatic movement with 45 h of power reserve.
Can I swim with the Seiko SJE101?
Yes. It is rated to 200 m and certified as an ISO 6425 diver.
Does the Seiko SJE101 have a date?
Yes, it shows the date.
How much is the Seiko SJE101?
The US list price was $2,800 on seikowatches.com when we checked on 23 Oct 2026. Prices change, so check before you buy.
Will the Seiko SJE101 fit my wrist?
By our sizing guide it sits best on wrists of about 15.9–17.7 cm (6.3–7.0 in). Use the fit checker on this page to test your own wrist.
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