Seiko SPB143 vs SPB453
The SPB453 replaced the SPB143 in Seiko's 1965 Heritage Diver's line. Here is exactly what changed, from Seiko's own spec pages.
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The short answer
The SPB453 is the smaller, more capable successor: its case is 0.5 mm smaller across, 0.2 mm thinner, and 1.2 mm shorter lug-to-lug (46.4 mm vs 47.6 mm). It moves from the 6R35 to the 6R55 calibre (72 h vs 70 h power reserve) and from 200 m to 300 m water resistance. Both take 20 mm straps and both are ISO 6425 divers per Seiko.
The SPB143 is discontinued, so you will mostly find it pre-owned or as leftover stock. Its last US list price was $1,200 (last US list); the SPB453 lists at $1,300 (US list).
Side-by-side specs
| Spec | Seiko SPB143 | Seiko SPB453 |
|---|---|---|
| Case diameter | 40.5 mm | 40 mm |
| Thickness | 13.2 mm | 13 mm |
| Lug-to-lug | 47.6 mm | 46.4 mm |
| Lug width | 20 mm | 20 mm |
| Calibre | 6R35 | 6R55 |
| Movement | Automatic | Automatic |
| Power reserve | 70 h | 72 h |
| Hacking seconds | Yes | Yes |
| Water resistance | 200 m | 300 m |
| ISO 6425 diver | Yes | Yes |
| Crystal | Sapphire | Sapphire |
| Case material | Stainless steel | Stainless steel |
| Ships on | Bracelet | Bracelet |
| Weight | Not published by Seiko | 168 g |
| US list price | $1,200 (last US list) | $1,300 (US list) |
| Status | Discontinued (succeeded by SPB451/SPB453, 2024) | In production |
| Suits wrists of about our sizing guide | 16.2–18.1 cm | 16.0–17.9 cm |
Specs summarised in our own words from the brand's product pages: SPB143 source (checked 23 Oct 2026) SPB453 source (checked 23 Oct 2026). "Not published" means the brand page we checked doesn't list it, so we leave it blank rather than guess.
Same specs, different dial: the SPB451 matches the SPB453 on every published dimension.
Wrist fit
Lug-to-lug (tip of the top lugs to tip of the bottom lugs) decides whether a watch overhangs your wrist more than the diameter does. Enter your wrist to see how each one should wear.
- Seiko SPB143 –
- Seiko SPB453 –
Same rule of thumb as Watch Finder: case diameter of about 23.5% of your wrist circumference (−2 mm to +2.5 mm), and lug-to-lug no longer than about 29% of it plus 1 mm. A guide, not a rule; flat or round wrists differ.
Strap and lug-width fit
- Seiko SPB143: 20 mm lugs, ships on bracelet
- Seiko SPB453: 20 mm lugs, ships on bracelet
All of these share the same lug width, so straps move between them freely. Seiko does not publish spring-bar diameter or a strap code, so check the hole size on any aftermarket strap. More in our SPB143 strap guide and the Seiko lug width chart.
Which should you buy?
The shorter 46.4 mm lug-to-lug is the biggest practical change. Our sizing guide puts the SPB453 at 16.0–17.9 cm and the SPB143 at 16.2–18.1 cm, so on the smallest wrists the 1.2 mm matters.
If you can find a good example under the SPB453's list price, you get nearly the same design, sapphire crystal and 200 m ISO diver rating for less.
It is the current model, so it is the one you are more likely to find new, including on Amazon.
Both are 20 mm, so the same straps fit both.
Prices and where to buy
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Questions
Is the SPB453 smaller than the SPB143?
Yes. Per Seiko, the SPB453 is 40 mm across, 13 mm thick and 46.4 mm lug-to-lug. The SPB143 is 40.5 mm, 13.2 mm and 47.6 mm.
What movement is in each?
The SPB143 uses the Seiko 6R35 automatic (70 h power reserve). The SPB453 uses the 6R55 (72 h).
Do they take the same straps?
Yes. Both have 20 mm lugs according to Seiko, so any 20 mm strap or bracelet with the right spring-bar fit will work on either.
Is the SPB143 discontinued?
Yes. Our records show it as discontinued and succeeded by the SPB451 and SPB453 in 2024. The SPB451 shares the SPB453's specs with a different dial.
Which is better for swimming?
Both are ISO 6425 divers. The SPB453 has the higher rating (300 m vs 200 m), though both are far beyond what swimming needs.
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.