All Seiko lines › Prospex › Sea
“Tuna”
Seiko Prospex Sea, 52.4 mm, 17.4 mm thick (8L35)
Collector nickname. Where the name comes from
1 version of this watch is on Seiko's own sites right now, across 3 regions. Last checked Nov 13, 2026.
Estimated US price: $3,900 Seiko US list price.
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
- 8L35
- Case diameter
- 52.4 mm
- Thickness
- 17.4 mm
- Lug to lug
- 53.5 mm
- Variants listed now
- 1
- Regions
- 3
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 |
|---|---|---|---|---|---|---|---|---|
 | SLA042 Also coded SLA042J1 | Not published | Silicone 158 g | Not stated | Regular | 3 regions Australia, Middle East, USA | 3,900 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
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 | 28,800 vibrations per hour (8 beats per second) Stop second hand function Date display | Seiko product page |
| Power reserve / battery | Approx. 50 hours | Seiko product page |
| Water resistance | 1000m / 3300ft for saturation diving | Seiko product page |
| Crystal | Sapphire crystal | Seiko product page |
| Lug width | 22 mm | Seiko product page |
| Seiko case codes | 8L35-01B0 | Seiko catalog data |
Why these share a page
Every version here is published by Seiko with calibre 8L35 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 SLA042. “So, in Seiko’s current lineup, there’s one quartz and one automatic monocoque Tuna model, the SBBN047 and SBDX038 (or SLA042).” | Fratello read 2026-11-12 |
|---|
Related lines
- “Tuna” · Seiko Prospex Sea, 52.4 mm, 17.2 mm thick (8L35)
Same calibre and diameter, different published case
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