Seiko SPB177
Ref. SPB177 · In production
- Case45 mm
- Thick12.9 mm
- Lug-to-lug52.6 mm
- Water res.200 m
- MovementAutomatic
- CrystalSapphire
Overview
The Seiko SPB177 is a diver watch from the Prospex collection, part of the Sea family. It has a 45 mm stainless steel case, 12.9 mm thick, 52.6 mm from lug to lug. Inside is a automatic movement (calibre 6R35) with 70 h of power reserve. You also get 200 m water resistance, a sapphire crystal and a bracelet.
Who it suits
- Wrists of roughly 18.1–20.0 cm (7.1–7.9 in), by our Watch Finder sizing guide
- Swimming, snorkelling and diving
Strengths
- Sapphire crystal resists scratches
- Certified to the ISO 6425 diver's standard (200 m)
- 70 h power reserve survives a weekend off the wrist
- Hacks and hand-winds, so it is easy to set
Trade-offs
- Long 52.6 mm lug-to-lug can overhang smaller wrists
Written by Watch.co from the published specs below. These are not owner reviews.
Full specifications
Case
| Case diameter | 45 mm | seikowatches.com · 23 Oct 2026 |
|---|---|---|
| Thickness | 12.9 mm | seikowatches.com · 23 Oct 2026 |
| Lug-to-lug | 52.6 mm | seikowatches.com · 23 Oct 2026 |
| Case material | Stainless steel | seikowatches.com · 23 Oct 2026 |
| Crystal | Sapphire | seikowatches.com · 23 Oct 2026 |
| Caseback | Screw | seikowatches.com · 23 Oct 2026 |
| Bezel | Unidirectional rotating | seikowatches.com · 23 Oct 2026 |
| Water resistance | 200 m | seikowatches.com · 23 Oct 2026 |
| ISO 6425 diver | Yes | 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 | 6R35 | seikowatches.com · 23 Oct 2026 |
| Made in-house | Yes | seikowatches.com · 23 Oct 2026 |
| Power reserve | 70 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) | $900 | 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.
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Questions about the Seiko SPB177
How big is the Seiko SPB177?
The case is 45 mm wide, 12.9 mm thick and 52.6 mm from lug to lug.
What movement does the Seiko SPB177 use?
It uses the 6R35 calibre, a automatic movement with 70 h of power reserve.
Can I swim with the Seiko SPB177?
Yes. It is rated to 200 m and certified as an ISO 6425 diver.
Does the Seiko SPB177 have a date?
Yes, it shows the date.
How much is the Seiko SPB177?
The US list price was $900 on seikowatches.com when we checked on 23 Oct 2026. Prices change, so check before you buy.
Will the Seiko SPB177 fit my wrist?
By our sizing guide it sits best on wrists of about 18.1–20.0 cm (7.1–7.9 in). Use the fit checker on this page to test your own wrist.
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