Seiko has unveiled two new Prospex Marinemaster dive watches, the HBF001 and HBF002, as modern reinterpretations of its 1968 Diver model. These updates include a new caliber, ceramic bezel inserts, and an improved bracelet clasp. Both models will be available from July 2026.
Seiko's Prospex Marinemaster series receives significant upgrades with the HBF001 regular-production model and the HBF002 limited edition of 1,000 pieces. Both feature a 42.6mm stainless steel case measuring 14.1mm thick and 49mm lug-to-lug, with 300m water resistance and a screw-down crown positioned slightly above 4 o'clock. The cases and five-row bracelets have super-hard coating for enhanced scratch resistance. A key improvement is the new folding clasp with a toolless micro-adjustment system, offering a 16mm extension in 2mm increments that can be retracted while worn. The bezels now use ceramic inserts—black for the HBF001 and blue for the HBF002—replacing previous steel versions. Powering both is the in-house caliber 8L45, running at 28,800 vibrations per hour with 35 jewels, a 72-hour power reserve, and accuracy of -5/+10 seconds per day. This replaces the prior 8L35 and is visible through an all-steel caseback. The HBF002, developed with the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), has a textured blue gradient dial inspired by the Mirai II research vessel's path through sea ice, a gold seconds hand, and light green Lumibrite indices. The HBF001 sports a matte black dial with the date at 3 o'clock and updated bezel numerals. These follow updates to the Marinemaster line less than 18 months ago with the SLA077 and SLA079, based on the same 1968 Diver. Prices rise to €3,800 for the HBF001 and €4,100 for the HBF002, compared to €3,000 for the previous SLA079. Availability starts in July 2026 at Seiko boutiques and select retailers worldwide.