Brand Guides / Seiko / Seiko Prospex Divers
Reviewed by the Fine Watch Guide team · October 2026
Seiko's Prospex divers carry a lineage that began with the 62MAS in 1965, and they remain some of the most worn and most modified tool watches in the world.
Seiko's dive watches are a story of steady evolution, from the 62MAS of 1965 through famous 1970s references to today's Prospex line, which includes many re-editions of classic designs. They're built to be used in water, and the way an owner wears one decides most of its service needs.
A dive watch is only as good as its seals. Gaskets age with time, heat and chlorine whether or not the watch is worn, and a diver that swims regularly should be pressure tested every year or two. At each full service, ask for new gaskets on the crown, caseback and crystal, and a test to the rated depth rather than a quick check.
Screw-down crowns need care too. Always screw the crown fully down before entering water, and don't operate it while wet. Damaged crown threads are one of the most common repairs on hard-worn divers.
Many current Prospex divers use Seiko's widely serviced automatic calibers, which most independents handle well. On the more affordable models, a shop may recommend replacing the movement if that's cheaper than an overhaul. On higher-end Prospex pieces, servicing the original movement is usually the better choice.
Bezels and inserts take knocks on a diver, and replacement parts are often available, but check that any replacement is genuine Seiko if originality matters to you.
Vintage Seiko divers are collectible, and value depends on original dials, hands and bezel inserts. They're also among the most heavily modified watches, with aftermarket parts widely sold. When buying, check that the dial printing, hands and bezel match the reference and era, and ask for photos of the movement. A specialist who knows vintage Seiko can confirm originality quickly.
If you own a vintage diver, look for a watchmaker who will service the movement while leaving the original cosmetic parts in place, and who can source period-correct gaskets.
Every year or two if you swim with it, and after any service or crystal replacement.
Yes. The 62MAS, from 1965, was Seiko's and Japan's first dive watch.
Usually, yes. If originality matters, use a genuine Seiko part rather than an aftermarket one.
For collectors of original watches, yes. Modifications are fine when disclosed, but they reduce value for buyers who want factory parts.
Seiko Prospex Divers owners use Seiko specialists for servicing, authentication and restoration.
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