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“Tuna”
Seiko Prospex Street Series diver's, 43.2 mm (4R36)
Collector nickname. Where the name comes from
1 version of this watch is on Seiko's own sites right now, across 1 region. Last checked Nov 13, 2026.
Estimated US price: About $585, converted from Seiko's list price in AUD.
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
- 43.2 mm
- Thickness
- 12.7 mm
- Lug to lug
- 44 mm
- Variants listed now
- 1
- Regions
- 1
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 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 | SRPE31 Also coded SRPE31K1 | Not published | Silicone 107 g | Stainless steel (hard coating) | Regular | 1 region Australia | 860 AUD Australia · Nov 13, 2026 about $585 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 | 20 mm | Seiko product page |
| Seiko case codes | 4R36-08A0 | 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. 2 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.
| “Tuna” | Collector nickname. Source names SRPE31. “First up are two new Tunas, the SRPE29 and SRPE31.” | Worn & Wound read 2026-11-12 |
|---|
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