All Seiko lines › Prospex › Sea
“Monster”
Seiko Prospex Sea diver's, 42.4 mm (4R36)
Collector nickname. Where the name comes from
10 versions of this watch are on Seiko's own sites right now, across 29 regions. Last checked Nov 13, 2026.
Estimated US price: About $490 to $630 from Seiko's US list price and its list prices in other countries, converted.
Retailers ask: no retailer listing matched yet.
Light Blue
Black
Photos are Seiko's own, shown from Seiko's sites. Click a photo to jump to that version.
- Calibre
- 4R36
- Case diameter
- 42.4 mm
- Thickness
- 13.4 mm
- Lug to lug
- 49.4 mm
- Variants listed now
- 10
- Regions
- 29
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 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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 | SRPG57 Also coded SRPG57K1 | Light Blue Seiko USA store tag | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 186 g | Stainless steel | Edizione speciale Save the oceanSave the Ocean Special EditionSave the Ocean Özel Üretim | 28 regions | 550 USD USA · Nov 13, 2026 | Not seen in stock 2 sellers checked | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (33 sites) and its list prices
Buying 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.
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 | SRPH75 Also coded SRPH75K1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 186 g | Stainless steel | Edizione speciale Save the oceanSave the Ocean Special EditionSave the Ocean Özel Üretim | 23 regions | 570 EUR France · Nov 13, 2026 about $630 in US dollars | Not seen in stock 1 seller checked | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (26 sites) and its list prices
Buying 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.
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 | SRPD25 Also coded SRPD25K1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 186 g | Stainless steel | Regular | 14 regions | 469 EUR France · Nov 13, 2026 about $520 in US dollars | No seller matched yet | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (15 sites) and its list prices
Buying options (0)No seller offer has been matched to this exact variant yet. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SRPE27 Also coded SRPE27J1, SRPE27K1 | Black Seiko USA store tag | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender 186 g | Stainless steel | Regular | 14 regions | 550 USD USA · Nov 13, 2026 | Not seen in stock 2 sellers checked | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (17 sites) and its list prices
Buying 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.
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 | SRPE09 Also coded SRPE09K1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender | Stainless steel | Regular | 11 regions | 520 EUR Portugal · Nov 13, 2026 about $550 in US dollars | No seller matched yet | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (12 sites) and its list prices
Buying options (0)No seller offer has been matched to this exact variant yet. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SRPD29 Also coded SRPD29K1 | Not published | Not stated 186 g | Stainless steel (hard coating) Translated from Seiko's regional page | Regular | 6 regions | 519 EUR Italy · Nov 13, 2026 about $560 in US dollars | No seller matched yet | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (6 sites) and its list pricesBuying options (0)No seller offer has been matched to this exact variant yet. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SRPF35 Also coded SRPF35K1 | Not published | Not stated 120 g | 不鏽鋼 (硬質鍍膜) Seiko's regional wording | Regular | 3 regions Hong Kong, Malaysia, Singapore | 3,980 HKD Hong Kong · Nov 13, 2026 about $505 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. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SRPD27 Also coded SRPD27K1 | Not published | Silicone 120 g | Stainless steel | Regular | 2 regions Australia, Hungary | 725 AUD Australia · Nov 13, 2026 about $495 in US dollars | No seller matched yet | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (2 sites) and its list pricesBuying options (0)No seller offer has been matched to this exact variant yet. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SRPF33 Also coded SRPF33K1 | Not published | Not stated Clasp: Three-fold clasp with push button release | Stainless steel | Regular | 1 region Philippines | 31,330 PHP Philippines · Nov 13, 2026 about $490 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. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SRPH13 Also coded SRPH13K1 | Not published | Silicone 120 g | Stainless steel (hard coating) | The Black Series Limited Edition | 1 region Australia | 825 AUD Australia · Nov 13, 2026 about $560 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
No retailer listing has been matched to a version on this line yet.
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 Day/Date display | Seiko product page |
| Power reserve / battery | Approx. 41 hours | Seiko product page |
| Water resistance | 200m / 660ft diver's | Seiko product page |
| Crystal | Hardlex Some variants are published as: Hardlex with magnified glass | Seiko product page |
| Lug width | 20 mm | Seiko product page |
| Seiko case codes | 4R36-07B0, 4R36-08B0, 4R36-09C0, 4R36-10L0, 4R36-11C0 | Seiko catalog data |
Why these share a page
Every version here is published by Seiko with calibre 4R36 and either the same Seiko case code or the same case size. 21 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.
| “Monster” | Collector nickname. Source names SRPD25. “Review: Seiko “Monster” SRPD25” | Worn & Wound read 2026-11-12 |
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