All Seiko lines › Prospex › Sea
“King Sumo” / “Sumo”
Seiko Prospex Sea diver's, 45 mm, 13.4 mm thick (6R35)
Collector nickname. Where the name comes from
5 versions of this watch are on Seiko's own sites right now, across 4 regions. Last checked Nov 13, 2026.
Estimated US price: About $1,125 to $1,250 from Seiko's US list price and its list prices in other countries, converted.
Retailers ask: $1,494 to $1,516 across 3 listings at 1 seller, 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
- 6R35
- Case diameter
- 45 mm
- Thickness
- 13.4 mm
- Lug to lug
- 52.6 mm
- Variants listed now
- 5
- Regions
- 4
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 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 | SPB321 Also coded SPB321J1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 190 g | Stainless steel | Regular | 4 regions Australia, Hungary, Ireland, USA | 1,200 USD USA · Nov 13, 2026 | From 1,370.00 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.
| ||||||||||||||||||
 | SPB323 Also coded SPB323J1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 190 g | Stainless steel | Regular | 4 regions Australia, Hungary, Ireland, USA | 1,200 USD USA · Nov 13, 2026 | From 1,370.00 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.
| ||||||||||||||||||
 | SPB375 Also coded SPB375J1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 190 g | Stainless steel (Bezel: Stainless steel with ceramic display) | PADI Special Edition | 4 regions Australia, Hungary, Ireland, USA | 1,200 USD USA · Nov 13, 2026 | From 1,350.00 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.
| ||||||||||||||||||
 | SPB325 Also coded SPB325J1 | Not published | Silicone 130 g | Stainless steel | Regular | 3 regions Australia, Hungary, USA | 1,650 AUD Australia · Nov 13, 2026 about $1,125 in US dollars | No seller matched yet | ||||||||||
Where Seiko lists it (3 sites) and its list pricesBuying options (0)No seller offer has been matched to this exact variant yet. | ||||||||||||||||||
 | SPB433 Also coded SPB433J1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 190 g | Stainless steel (hard coating)with ceramic bezel | LimitáltThe Black Series Limited Edition | 3 regions Australia, Hungary, USA | 1,250 USD USA · Nov 13, 2026 | No seller matched yet | ||||||||||
Where Seiko lists it (3 sites) and its list pricesBuying 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 | SPB375 | 1,350.00 EUR about $1,494 | Nov 13, 2026 |
| Seiko Boutique Ireland | SPB321 | 1,370.00 EUR about $1,516 | Nov 13, 2026 |
| Seiko Boutique Ireland | SPB323 | 1,370.00 EUR about $1,516 | 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 | Stop second hand function Date display | Seiko product page |
| Power reserve / battery | Approx. 70 hours | 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 | 6R35-02C0, 6R35-03A0 | Seiko catalog data |
Why these share a page
Every version here is published by Seiko with calibre 6R35 and either the same Seiko case code or the same case size. 10 reference codes lead to this page.
What people call it
A name is shown only where a source ties it to a reference on this page. Collector nicknames are not Seiko's names unless the row says so.
| “King Sumo” | Collector nickname. Source names SPB323J1. “Prospex King Sumo Grey Gradation Diver” | Seiko Watches India official online e-store (seikowatches.co.in) read 2026-11-12 |
|---|---|---|
| “Sumo” | Collector nickname. Source names SPB321J1, SPB323J1. “Here are the Seiko Sumo Prospex Diver 200m SPB321J1 & SPB323J1.” | Monochrome Watches read 2026-11-12 |
Related lines
- “Sumo” · Seiko Prospex Sea diver's, 45 mm, 12.9 mm thick (6R35)
Same calibre and diameter, different published case
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