There’s a specific kind of enthusiast who wants one watch to do it all. And for that person, Seiko’s 1968 Heritage Diver’s GMT has been one of the easiest recommendations in the sub-$2,000 game since it landed in 2023.
The catch? Seiko kept debuting meaningful improvements on limited and special editions while the standard green and black models soldiered on unchanged. That ends now, with the original references giving way to two upgraded successors: the green-dialed HBC001 and black-dialed HBC002.
The Trickle-Down Treatment
Over the past year, Seiko has used releases like the SPB534 and the white-dialed SPB519 to introduce a pair of genuinely useful updates to the platform. If you wanted the classic black or green colorway, though, you were stuck with the 2023 spec.
The new HBC001 and HBC002 change that, folding both upgrades into the permanent collection and officially replacing the SPB381 and SPB383 that started it all.
Deeper Water, Same Waistline
Upgrade number one is water resistance, which jumps from 200m to a properly professional 300m. Now, here’s the impressive part. Seiko managed to pull this off without adding a single millimeter, with the case holding steady at 12.9mm thick.
Upgrade number two lives in the clasp. The old diver’s extension is gone, replaced by a push-button slide adjuster offering roughly 15mm of tool-free travel across six 2.5mm steps. For anyone whose wrist swells on a summer afternoon (so, everyone), this is sure to be a hit feature.
Everything Worth Keeping
The rest of the formula carries over untouched. The 42mm stainless case keeps its mirror-polished sides and 4 o’clock crown, both nods to Seiko’s landmark 1968 professional diver, along with a ceramic bezel insert and sapphire crystal.
Inside beats the Caliber 6R54, a caller-style GMT that lets you jump the 24-hour hand independently in one-hour increments. With a 72-hour power reserve, it’s the longest of any Seiko mechanical movement.
Spec Sheet
Reference: HBC001 (Green) / HBC002 (Black)
Case Size: 42mm
Lug-to-Lug: 48.6mm
Case Thickness: 12.9mm
Case Material: Stainless steel with super-hard coating
Water Resistance: 300m
Movement: Seiko Caliber 6R54 automatic GMT
Power Reserve: Approx. 72 hours
Band: Stainless steel bracelet with tool-free microadjust clasp
Limited Edition?: No, permanent collection
Pricing & Availability
Both references are available now for $1,700, a $200 bump over the outgoing models. Interestingly, Seiko still lists the original SPB381 and SPB383 at $1,500, so bargain hunters who can live without the new clasp have a closing window. Head over to Seiko’s website to check them out.
Recap
Seiko Prospex 1968 Heritage Diver’s GMT HBC001 & HBC002
Seiko’s mainline 1968 Heritage GMT divers finally inherit the 300m water resistance and tool-free microadjust clasp its limited editions have been hoarding.
