Seiko refreshes its flagship Marinemaster diver with a new 8L45 movement, 72 hours power reserve, and new clasp system

Three years after reviving the Marinemaster brand, which saw Seiko release three compact dive watches in the heritage collection, the company is now refreshing its flagship dive watch with the release of the new Prospex Marinemaster 1968 Heritage Diver’s Watch HBF001 and the HBF002 JAMSTEC Limited Edition.

You would be forgiven to mistake the new Marinemaster HBF001 for the SLA079 at first, given just how visually indistinguishable they look from each other. But look closer, and you can spot a few differences, such as the position of the date window and the HBF001’s dial featuring the “3 days” text. The biggest differentiator however is the switch to the new 8L45 movement, a big step up over the aging 8L35 movement found in the SLA079. 

Updated Caliber 8L45 brings better accuracy and a longer power reserve

Thanks to the new caliber 8L45, the Marinemaster HBF001 offers up to 72 hours of power reserve when fully wound, a significant improvement over the 50 hour power reserve offered by the caliber 8L35. Timekeeping accuracy also sees a big improvement, with the new watch boasting a daily time deviation of just +10 seconds to -5 seconds, which Seiko claims is the highest accuracy among its current mechanical movements.

Seiko’s new one-push diver adjuster clasp system is another big highlight of the package. The newly developed clasp allows up to 16mm of extension, with eight fine adjustment steps of 2mm each, all by simply sliding the clasp inside. Seiko adds that even when the clasp is closed, you can retract the extension. Overall, it’s a big improvement over the stamped clasps used previously.

JAMSTEC limited edition with a captivating 3D dial

The HBF002 JAMSTEC Limited Edition, created in collaboration with the Japan Agency for Marine-Earth Science and Technology, takes a more expressive approach. Celebrating upcoming Arctic research, this exclusive model (limited to 1000 units worldwide) features a three-dimensional blue gradient dial that evokes an icebreaker cutting through sea ice, complemented by a matching blue ceramic bezel.

Both 1968 Heritage models boast 300m diving water resistance, unidirectional rotating bezels, dual-curved sapphire glass, and a robust 42.6mm stainless steel case protected with DiaShield coating. They also feature bright LumiBrite accents for superior visibility even in dark underwater environments and magnetic resistance up to 4800 A/m.

Pricing & Availability

The Seiko Prospex Marinemaster 1968 Heritage HBF001 and JAMSTEC Limited Edition HBF002 are priced at $3,600 / £3,300 / €3,800 and $3,900 / £3,550, €4,100, respectively. The watches are set to go on sale across the US, UK, Europe, and Japan in July.