All Seiko lines › Prospex › Sea
“Turtle”
Seiko Prospex Sea diver's, 45 mm, 13 mm thick (4R36)
Collector nickname. Where the name comes from
3 versions of this watch are on Seiko's own sites right now, across 13 regions. Last checked Nov 13, 2026.
Estimated US price: About $520 to $535, converted from Seiko's list prices in AUD, EUR, GBP and more.
Retailers ask: no retailer listing matched yet.
Photos are Seiko's own, shown from Seiko's sites. Click a photo to jump to that version.
- Calibre
- 4R36
- Case diameter
- 45 mm
- Thickness
- 13 mm
- Lug to lug
- 47.7 mm
- Variants listed now
- 3
- Regions
- 13
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 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 | SRPD21 Also coded SRPD21K1 | Not published | Not stated Clasp: Three-fold clasp with secure lock , push button release with extender | Stainless steel | Regular | 13 regions | 469 EUR Italy · Nov 13, 2026 about $535 in US dollars | No seller matched yet | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Where Seiko lists it (14 sites) and its list prices
Buying options (0)No seller offer has been matched to this exact variant yet. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SRPD46 Also coded SRPD46K1 | Not published | Silicone Translated from Seiko's regional page | Stainless steel (hard coating) Translated from Seiko's regional page | Regular | 2 regions Indonesia, Singapore | 668.80 SGD Singapore · Nov 13, 2026 about $520 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. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 | SRPD45 Also coded SRPD45K1 | Not published | Silicone | Stainless steel (hard coating) | Regular | 1 region Singapore | 687 SGD Singapore · Nov 13, 2026 about $535 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 | Seiko product page |
| Lug width | 22 mm | Seiko product page |
| Seiko case codes | 4R36-07D0, 4R36-07K0, 4R36-07L0 | 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. 6 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.
| “Turtle” | Collector nickname. Source names SRPD21K. “Meet the Save the Ocean Great White Shark edition ’turtle’ diver, AKA the Seiko SRPD21K.” | Time+Tide read 2026-11-12 |
|---|
Related lines
- “King Turtle” · Seiko Prospex Sea diver's, 45 mm, 13.2 mm thick (4R36)
Same calibre and diameter, different published case - “Turtle” · Seiko Prospex Sea diver's, 45 mm, 13.4 mm thick (4R36)
Same calibre and diameter, different published case
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