Seiko Prospex 1965 Diver Re-creation SPB143 vs Seiko Prospex Alpinist SPB121

Side-by-side at a glance. Click a watch above to open the full reference page.

	Seiko SPB143J1	Seiko SPB121J1
Model	Prospex 1965 Diver Re-creation SPB143	Prospex Alpinist SPB121
Caliber	Seiko Cal. 6R35 -- in-house automatic, 28,800bph, 70h PR, 24j; hackable, manual-wind; upgraded from 6R15; used widely in Presage and Prospex lines	Seiko Cal. 6R35 -- in-house automatic, 28,800bph, 70h PR, 24j; hackable, manual-wind; upgraded from 6R15; used widely in Presage and Prospex lines
Case size	40.5mm	39.5mm
Lug-to-lug	46mm	46mm
Years produced	2020–present	2020–present
Brand tier	enthusiast	enthusiast
Era	modern	modern
Movement tier	Unclassified movement	Unclassified movement
Market median (excellent / full-set)	n/a	n/a
Typical range	n/a	n/a
Confidence	low	low
Categories	dive, sport	sport
Editorial	yes	yes
Collector note	n/a	best value: In-house Hi-Beat movement with a compass bezel at a price that undercuts the vast majority of Swiss equivalents.