Seiko Turtle strap size and lug width
Lug widths for the 45 mm Turtle-case divers, the sapphire versions and the 41 mm SPB317, from Seiko's spec pages.
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The short answer
Turtle-case Seikos take 22 mm straps. The SRP777, SRPE93 and SRPE99 share a 45 mm case, 13.4 mm thick, with 22 mm lugs; Seiko doesn't publish their lug-to-lug. The versions with a sapphire crystal and ceramic bezel insert (SRPE05, SRPF77, SRPK01, often called "King Turtle") are also 22 mm, with a published 47.7 mm lug-to-lug.
The exception is the SPB317, a smaller 41 mm 6R35 Prospex diver that takes 20 mm straps.
Seiko sells all of these as Prospex "Sea". "Turtle" and "King Turtle" are collector names; we group references here by matching case dimensions from Seiko's pages. That grouping is our inference.
Turtle family at a glance
Use the table to compare widths and sizes. Our SPB317 vs SRPE93 comparison covers the size difference in detail.
| SRP777 | Prospex | 22 mm | 45 mm | n/p | 13.4 mm | Silicone | – |
| SRPE93 | Prospex · Sea | 22 mm | 45 mm | n/p | 13.4 mm | Silicone | – |
| SRPE99 | Prospex · Sea | 22 mm | 45 mm | n/p | 13.4 mm | Bracelet | – |
| SRPE05 | Prospex · Sea | 22 mm | 45 mm | 47.7 mm | 13.2 mm | Silicone | – |
| SRPF77 | Prospex · Sea | 22 mm | 45 mm | 47.7 mm | 13.2 mm | Silicone | – |
| SRPK01 | Prospex · Sea | 22 mm | 45 mm | 47.7 mm | 13.2 mm | Bracelet | – |
| SPB317 | Prospex · Sea | 20 mm | 41 mm | 46.9 mm | 12.3 mm | Silicone | – |
Click a column heading to sort. n/p = not published by the brand. Quick-release "Yes" only where the brand page says so; "–" means not stated, not "no".
Which strap type?
- Rubber or silicone: the practical choice for swimming and hot weather. It doesn't absorb water and rinses clean.
- Fabric single-pass or two-piece nylon: light and cheap. A single-pass strap runs under the case, which adds a little height on the wrist.
- Leather: dressier, but water and sweat shorten its life. Keep it off dive watches you actually swim with.
- Steel bracelet: the most durable, but aftermarket bracelets need end links shaped for the specific case, which brands rarely publish. Buy one listed for your exact reference.
Spring bars: what Seiko doesn't publish
Seiko lists lug width, but not spring-bar diameter or a strap code. Aftermarket straps vary in how large their spring-bar holes are, so before you buy, check the strap's stated hole size against the bars you'll use, or reuse the original bars if they fit. See our spring bars and tools guide.
Shop straps
Paid links to Amazon search results. Check the listed width and spring-bar hole size against the table above.
Questions
What lug width is the Seiko Turtle?
22 mm, per Seiko, for the SRP777, SRPE93, SRPE99 and the sapphire SRPE05, SRPF77 and SRPK01.
What is the Seiko Turtle lug-to-lug?
Seiko doesn't publish it for the SRP777, SRPE93 or SRPE99. For the SRPE05, SRPF77 and SRPK01 it lists 47.7 mm.
Does the SPB317 take the same strap as the Turtle?
No. The SPB317 is 20 mm, the Turtle-case models are 22 mm.
Do Turtles need special spring bars?
Seiko doesn't publish spring-bar diameter. Many aftermarket straps are made with Seiko divers in mind, but check the strap's hole size against the bars you'll fit.
Watch.co is independent and not affiliated with any brand. We haven't handled these watches for this page: everything here comes from brand-published specs and our own analysis. Brand names are used only to identify products.