There is a reliable rhythm to Seiko's anniversary years, and it goes something like this: a quietly profound bit of corporate history, a deep look into the archives, and then a handful of limited editions calibrated to remind us why we fell for the brand in the first place. K. Hattori opened the doors of his shop in Tokyo's Ginza district in 1881 — that's 145 years ago this year — and to keep the celebration rolling, Seiko Prospex has unveiled two new divers that lean on one of the brand's most beloved visual cues: Seiko Blue.
Meet the Prospex 1965 Heritage Diver HBC005 and the Prospex Samurai HBB001.
A Color, Not Just A Reference Number
If you've spent any time on enthusiast forums, "Seiko Blue" has become a kind of shorthand — a saturated, slightly cool, slightly electric tone that has appeared on bezels, dials, and seconds hands since the 1960s. It's the brand's house blue, and these two limited editions are built around it. Pair that bezel color with a brushed silver-white dial and a single blue seconds hand, and you get a look that feels both retro and very 2026. Restrained, but it pops.
Both watches also debut Seiko's new alphanumeric reference scheme. Those leading letters aren't random; they're the start of a tidier global system that's slowly replacing the old SPB/SRPB sprawl. Filing cabinets across the watch world rejoice.
The Prospex 1965 Heritage Diver HBC005
The HBC005 is the more elegant of the pair, and the one most of us were probably hoping for. It builds on the 2024 update of Seiko's 1965 Heritage Diver — a watch that traces a direct line back to the 62MAS, Japan's first dive watch, released (you guessed it) in 1965. After years of slightly oversized Prospex divers, the platform now sits at a deeply wearable 40mm wide, 13mm thick, with a 46.4mm lug-to-lug. That last number is the headline. On a flat wrist, this is going to wear like a modern Submariner.
The case and bracelet are stainless steel with Seiko's super-hard coating, and a domed sapphire crystal with internal anti-reflective treatment replaces the Hardlex of yore — a small detail, but one that quietly pushes the watch up a tier. Water resistance is rated to 300 meters, the bezel insert is Seiko Blue aluminum, and inside is the calibre 6R55, the modern automatic with three full days of power reserve.
The dial is where this one earns its silver-and-blue thesis: a lightly brushed silvery-white base, embossed lume-filled markers, and a single blue seconds hand sweeping past them. It is, dare I say, charming in a way that several recent Prospex releases haven't been.
The bracelet inherits the updated clasp introduced on last year's SPB511, with 15mm of on-the-fly micro-adjustment across six 2.5mm increments via push-button. As someone whose wrist swells half a size in summer, this is a quiet but meaningful upgrade — the kind of thing that turns a good diver into one you actually wear daily.
The Prospex Samurai HBB001
The Samurai is the angular cousin, and Seiko has wisely chosen to celebrate it. Based on the redesigned 2024 Samurai platform, the HBB001 measures 41.7mm by 12.3mm with a 49.5mm lug-to-lug — still big, still sharp, but considerably more wearable than the broad-shouldered Samurai of memory. The lugs are faceted like sword edges (the metaphor that gave the watch its nickname), and the case planes are crisper than ever.
The standout detail here is the two-tone bezel insert: silver from 12 to 3, then Seiko Blue all the way around. It's a clean nod to the Pepsi-and-Coke world of dual-color bezels without committing to red. The brushed silver dial is slightly darker than its 1965 counterpart, the markers are the signature pointed indices, and — naturally — there's a blue seconds hand for continuity.
You get Hardlex (not sapphire), the calibre 4R35 automatic with 41 hours of power reserve, and 200m of water resistance on a three-link steel bracelet with a folding clasp. It is, in every sense, the gateway anniversary diver — the one a first-time enthusiast might actually pull the trigger on.
Price and Availability
The HBC005 is a limited edition of 4,000 pieces at $1,400 USD (around EUR 1,500). The Samurai HBB001 runs 9,999 pieces at $595 USD (around EUR 650). Both arrive at retailers worldwide in June 2026.
Neither watch reinvents anything. Both lean on platforms Seiko refined just two years ago, dressed in a color scheme the brand has been quietly perfecting since the Nixon administration. That, frankly, is fine. The HBC005 is the connoisseur's pick — sapphire crystal, 72-hour movement, refined proportions, and a clasp that finally addresses the everyday gripe. The HBB001 is the punchier, more accessible buy that gets you into a real Samurai for under $600. Together, they're a smart 145th-birthday flex: the heritage piece for the long-time collector, and the entry point for whoever finds Seiko next.
If you're going to mark a century-and-a-half by reaching into your own paintbox, "Seiko Blue" is about as fitting a color as it gets.
Specifications
Seiko Prospex 1965 Heritage Diver HBC005
Case: 40mm × 13mm, 46.4mm lug-to-lug, stainless steel with super-hard coating
Crystal: Curved sapphire with internal anti-reflective coating
Bezel: Unidirectional, Seiko Blue aluminum insert
Movement: Calibre 6R55, automatic, 3Hz, 72-hour power reserve
Water resistance: 300m diver's
Bracelet: Steel with super-hard coating, push-button micro-adjust clasp (15mm range)
Limited edition: 4,000 pieces
Price: $1,400 USD
Available: June 2026
Seiko Prospex Samurai HBB001
Case: 41.7mm × 12.3mm, 49.5mm lug-to-lug, stainless steel
Crystal: Hardlex
Bezel: Unidirectional, two-tone aluminum insert (silver and Seiko Blue)
Movement: Calibre 4R35, automatic, 3Hz, 41-hour power reserve
Water resistance: 200m diver's
Bracelet: Steel three-link with folding clasp
Limited edition: 9,999 pieces
Price: $595 USD
Available: June 2026