
41 watches that match on case size, movement family, and price band. Sorted by how close the match is.
The closest alternative to the Seiko Monster Automatic 200M is the Seiko 5 Sports Dual-Crown Diver SRPB29 ($399) — shared caliber (Seiko 4R36) and Pro diver. If price is the constraint, the Orient AA02 Diver Watch at $285 covers most of the same brief. From the independents, the Squale 1521 Classic COSC is the standout microbrand take — common cross-shop and Pro diver.
Independent makers covering the same brief, usually with something the mainstream brands don't.
Established brands covering the same brief at a comparable price: same case size, similar movement family. Often the deciding click for a new buyer.
If the price is the only thing keeping you off this watch, these get you most of the way there for less.
Where the same idea goes when budget isn't the constraint: luxury upgrades and step-ups.