Marinemaster Professional

Seiko’s heritage in diver’s watches began in 1965 with the creation of Japan’s first diver’s watch. In the 60 years since, Seiko has continuously advanced in diver’s watchmaking to meet the demands of professional divers and adventurers alike. In 1968, Seiko introduced its first diver’s watch with 300m water resistance and a 10-beat automatic movement. In 1975, Seiko pushed the boundaries further with a 600m diver’s watch featuring a one-piece titanium case, an outer case protector, and a specially developed L-shaped gasket that made it impervious to helium. These two iconic watches forever changed the standard of diver’s watchmaking.

This new creation from Seiko Prospex commemorates the 60th anniversary of Seiko’s first diver’s watch. The dial and case design echo the iconic 1968 classic while its robust construction draws inspiration from the groundbreaking diver’s watch born in 1975.

The new watch features a dynamic embossed dial pattern that evokes shinkai, or “the deep sea,” and a blue gradient that deepens toward the outer edge captures the mysterious and beautiful underwater world. A thick, clear coating adds a lustrous finish and enhances the dial’s visual depth.

To ensure reliability and safety, the indexes are formed as part of the dial through a molding process, ensuring they remain firmly in place even under impact. Like its legendary 1975 predecessor, the watch features a one-piece titanium case with water resistance to 600 meters, suitable for saturation diving, and uses a specially developed L-shaped gasket that prevents helium infiltration, eliminating any need for a helium escape valve.

The watch is powered by Caliber 8L45, a newly developed movement that represents the pinnacle of Seiko’s mechanical watchmaking. This movement incorporates Spron, Seiko’s proprietary alloy. A thinner, longer mainspring enables a 72-hour power reserve, while an improved method for securing the movement within the case enhances overall durability. The new movement is also highly accurate: Caliber 8L45 offers a daily accuracy of +10 to –5 seconds, combining resilience and precision in a true professional diver’s watch.