The Seiko SKX007 and SKX009 are the most talked-about affordable watches ever made, and Seiko discontinued them. The official replacement is the Seiko 5 Sports SRPD line, which shares the case silhouette and almost none of the arguments. If you are trying to decide between hunting down a used SKX and buying a new SRPD, the comparison comes down to two specs pulling in opposite directions.
The movement got better. The SKX used the 7S26, which neither hacks (the seconds hand does not stop when you set the time) nor hand-winds (you shake it to start it). The SRPD uses the 4R36, which does both. That is a genuine, daily-noticeable upgrade and it is not close.
The water resistance got worse. The SKX was a 200m ISO 6425 dive watch with a screw-down crown. The SRPD is 100m with no screw-down crown — diver-styled rather than a dive tool. If the reason you wanted an SKX was that it was a real diver at a low price, the SRPD does not replace it, and we would point you at the Prospex Turtle instead.
The movement: 7S26 versus 4R36
Both are Seiko automatics, both are famously robust, and both are serviceable more or less indefinitely. The 4R36 adds two things. Hacking stops the seconds hand when you pull the crown, so you can set the watch to the exact second instead of within half a minute. Hand-winding lets you wind the mainspring from the crown, so a watch that has been in a drawer starts with twenty turns instead of a shake. Neither changes what the watch does, but both remove daily friction, and the 4R36 is the movement Seiko still builds today.
The water resistance: 200m ISO versus 100m
This is where the SKX earns its reputation. It was ISO 6425 certified with a screw-down crown — a genuine dive instrument sold for a price that made no sense. The SRPD, at 100m without a screw-down crown, is a swim-and-shower watch. For the vast majority of owners, who do not dive, that distinction never matters in practice. For anyone who bought an SKX because it was a certified tool, it is the whole argument.
Buying a used SKX in 2026
Because production ended, SKX prices on the used market have risen and the supply is entirely secondhand. That brings the usual risks: unknown service history, aftermarket parts fitted by previous owners, and — because the SKX is the single most-modded watch in existence — a real chance the dial, hands or bezel insert are not Seiko's. A movement service costs real money on top of the purchase. Buying new removes all of that.
The honest recommendation
Buy the SRPD if you want a Seiko 5 to wear every day, swap straps on, and not think about — it is new, warrantied, has the better movement and costs less than a good used SKX. Buy a Prospex Turtle if what you actually wanted was the SKX's 200m ISO dive spec; it is the true spiritual successor on capability, and it is still remarkable value. Buy a used SKX only if you specifically want that watch, understand the movement's limitations, and can verify what you are getting.
Both take the same straps
The SKX, the SRPD and the Turtle are all 22mm. That is the reason the SKX aftermarket is so enormous and the reason it transferred straight to the SRPD — every strap, bezel insert and bracelet made for the old watch fits the new one. Start with our NATO picks, or check the lug width chart.
