Seiko releases two new automatic GMT divers with a new adjustable clasp and Caliber 6R54

After updating its flagship Marinemaster dive watch in March, Seiko is adding two new watches with GMT functionality to its classic 1968 Heritage Diver’s collection. The new Prospex HBC001 and HBC002 are updated versions of the SPB381 and SPB383 and offer more robust water resistance and a new micro-adjust clasp.

The Seiko Prospex HBC001 features a green dial with a matching unidirectional rotating dive bezel, while the HBC002 is offered in a classic black finish. Apart from the colorway, there’s virtually no difference between these models, with both watches featuring a gold-accented GMT hand and red-dotted second hand and Lumibrite-applied indexes, hands, and bezel for low-light visibility. 

As far as the looks are concerned, we see literally no change between the new HBC001/HBC002 and the older SPB381 and SPB383. There’s no change to the movement either, with the newer models featuring the same Seiko caliber 6R54, a high-performance mechanical GMT movement first introduced in March 2023. This means the new watches offer up to 72 hours or 3 days of power reserve, a daily time deviation of +25 to -15 seconds, a 24-hour hand, a date display, and up to 4,800 A/m magnetic resistance. 

The biggest improvement here is the new clasp system, which Seiko first introduced on its flagship Marinemaster, and it lets you adjust the clasp in six precise steps, "each measuring about 2.5mm, for a total range of approximately 15mm." Not only does this allow you to find the perfect fit for everyday wear, but Seiko says it’s especially helpful for accommodating changes in wrist size during diving. 

Beyond the clasp, another notable upgrade for these models is improved durability. The new HBC001 and HBC002 boast up to 300 meters of water resistance, representing a solid step up from the 200-meter limit found on the older SPB variants.

Pricing & Availability

The Seiko HBC001 and HBC002 will hit shelves in the US, UK, Australia, and Europe this coming May. They are officially priced at £1,600 and A$2,800 in the UK and Australia respectively, though US pricing remains unknown for the time being.

View Seiko Prospex SRPH59 Special Edition dive watch on Amazon