All Seiko lines › Prospex › Sea
Seiko Prospex Sea GMT diver's, 42 mm, 12.9 mm thick (6R54)
5 versions of this watch are on Seiko's own sites right now, across 24 regions. Last checked Nov 13, 2026.
Estimated US price: About $1,410 to $2,120 from Seiko's US list price and its list prices in other countries, converted.
Retailers ask: $1,500 to $2,158 across 3 listings at 2 sellers, checked Nov 13, 2026. See the sellers
Photos are Seiko's own, shown from Seiko's sites. Click a photo to jump to that version.
- Calibre
- 6R54
- Case diameter
- 42 mm
- Thickness
- 12.9 mm
- Lug to lug
- 48.6 mm
- Variants listed now
- 5
- Regions
- 24
Listed means the watch was on an official Seiko regional site or store at the last check. It does not mean it is in stock, and it does not tell us whether Seiko is still making it.
Versions listed now
Same case and movement in every row. What changes is the colour, the strap or bracelet, the finish and where Seiko sells it. Seiko's spec sheets don't state dial colour, so a colour appears only where Seiko's US store tags one.
| Photo | Reference | Colour | Strap / bracelet | Case | Edition | Listed in | Seiko list price | Buy | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 | SPB439 Also coded SPB439J1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 177 g | Stainless steel (Bezel: Stainless steel with ceramic display) | 1968' Diver's Re-interpretation GMT Save the Ocean1968' Diver's Yeniden Üretim GMT Save the Ocean ModeliEdição Limitada Save the Ocean | Reinterpretação Moderna do Diver's de 1968 com GMTLimitált | 20 regions | 1,800 EUR France · Nov 13, 2026 about $2,120 in US dollars | No seller matched yet | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (23 sites) and its list prices
Buying options (0)No seller offer has been matched to this exact variant yet. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SPB381 Also coded SPB381J1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 176 g | Stainless steel (Bezel: Stainless steel with ceramic display) | 1968 Heritage Diver's GMT1968 Heritage Diver's GMT Watch | 5 regions | 1,500 USD USA · Nov 13, 2026 | From 1,500.00 USD Teddy Baldassarre · 2 sellers checked | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (5 sites) and its list pricesBuying options (2)Offers seen available at the last check come first, then by item price. Shipping, taxes and import charges are not included. Commission never affects the order.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SPB383 Also coded SPB383J1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 176 g | Stainless steel (Bezel: Stainless steel with ceramic display) | 1968 Heritage Diver's GMT1968 Heritage Diver's GMT Watch | 4 regions Australia, China, Hungary, USA | 1,500 USD USA · Nov 13, 2026 | No seller matched yet | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (4 sites) and its list pricesBuying options (0)No seller offer has been matched to this exact variant yet. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SPB385 Also coded SPB385J1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 176 g | Stainless steel (Bezel: Stainless steel with ceramic display) | LimitáltSeiko Watchmaking 110th Anniversary Seiko Prospex Save the Ocean Limited Edition | 4 regions Australia, Hungary, Ireland, USA | 1,700 USD USA · Nov 13, 2026 | From 1,950.00 EUR Seiko Boutique Ireland · 1 seller checked | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (4 sites) and its list pricesBuying options (1)Offers seen available at the last check come first, then by item price. Shipping, taxes and import charges are not included. Commission never affects the order.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SBEJ021 | Not published | Not stated 176 g | Stainless steel (ceramic bezel insert) Translated from Seiko's regional page | ダイバーズ 1968 ヘリテージ GMT | 1 region Japan | 225,500 JPY Japan · Nov 13, 2026 about $1,410 in US dollars | No seller matched yet | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (1 site) and its list prices
Buying options (0)No seller offer has been matched to this exact variant yet. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where to buy
Asking prices for new watches at the last check. Each was in stock at that check, but stock moves, and shipping, tax and import charges are not included. Each reference links to the seller's page.
| Seller | Version | Asking price | Checked |
|---|---|---|---|
| Seiko Boutique Ireland | SPB381 | 1,700.00 EUR about $1,882 | Nov 13, 2026 |
| Seiko Boutique Ireland | SPB385 | 1,950.00 EUR about $2,158 | Nov 13, 2026 |
| Teddy Baldassarre | SPB381 | 1,500.00 USD | Nov 13, 2026 |
Estimated US prices use Seiko's US list price where there is one. Otherwise they are the middle of Seiko's list prices in other countries, converted at rates dated Nov 12, 2026 from ExchangeRate-API (free open endpoint). Those list prices include each country's sales tax, so a converted figure usually runs higher than a US price would. Retailer prices are asking prices on the date shown, not sold prices, and leave out shipping, tax and import charges.
The build
| Movement | Automatic with manual winding | Seiko product page |
|---|---|---|
| Functions | 24-hour hand (dual time display function) Stop second hand function | Seiko product page |
| Power reserve / battery | Approx. 72 hours(3 days) | Seiko product page |
| Water resistance | 200m / 660ft diver's | Seiko product page |
| Crystal | Sapphire crystal | Seiko product page |
| Lug width | 20 mm | Seiko product page |
| Seiko case codes | 6R54-00C0, 6R54-00D0, 6R54-00E0 | Seiko catalog data |
Why these share a page
Every version here is published by Seiko with calibre 6R54 and either the same Seiko case code or the same case size. 9 reference codes lead to this page.
Related lines
- Seiko Prospex Sea GMT diver's, 42 mm, 13.3 mm thick (6R54)
Same calibre and diameter, different published case
Holden's Watch Desk is an independent catalog. It is not affiliated with, sponsored by or endorsed by Seiko. Seiko and its model names are trademarks of their owners, and the product photos are Seiko's, shown from Seiko's own sites to identify each watch. To report a mistake or ask for something to be removed, email holden@holdenswatchdesk.com.