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DOXA and Belmont take the shine off the SUB 300 Beta Frogger

Sandblasted steel, a kelp-green dial and orange hands give Belmont's DOXA collaboration its own identity, without a second logo on the dial.

Hen & Mills Editorial · 4 min read · 26 August 2026

• DOXA and Belmont Watches have created a SUB 300 Beta collaboration inspired by the Navy's underwater demolition teams and Coronado, California.
• The 42.5 mm steel case is fully sandblasted, framing a textured kelp-green dial with applied black indices and oversized orange hands.
• The numbered limited edition costs US$2,890 through Belmont Watches, with a steel bracelet and green nylon NATO strap included in the package.

There is a particular sort of collaboration I like, where the partner has clearly changed the watch but has resisted signing its name across the middle. Belmont Watches has taken that approach to its DOXA project, leaving the San Diego retailer's name off the dial and letting the finish do much of the talking. The result is green, orange and thoroughly matte, with a local naval connection carried on the back rather than shouted across the front: the DOXA × Belmont SUB 300 Beta Frogger.

Belmont describes the watch as a tribute to the Navy's Underwater Demolition Teams and their connection to Coronado, California. That is the inspiration for a civilian collaboration, not a claim that this is military-issued equipment. It also gives the design a place to start: a kelp-green dial, subdued metal and a caseback showing Coronado Island. What interests me is how little of that backstory you need to know to understand the watch, because the colour and surface treatment already make a coherent argument.

A broad case without the bright edges

DOXA and Belmont use a 42.5 mm case in 316L stainless steel, completely sandblasted rather than broken up with polished surfaces. At 11.95 mm thick and 44.5 mm from lug to lug, it is broad across the wrist without adding much length beyond that diameter, although dimensions cannot substitute for trying it on. The flat sapphire crystal keeps the profile straightforward, while the 300-metre water-resistance rating and helium release valve retain the diver's equipment beneath the changed finish. The architecture is recognisably SUB 300 Beta.

That distinction matters, because this is a particular interpretation of an existing platform, not a new case being introduced under a familiar name. DOXA's current SUB 300 Beta Professional has the same published dimensions and a sunray dial with a stamped wave pattern, while Belmont has chosen an altogether rougher-looking green texture. Against the softly grained steel, it makes the watch look more like a piece of equipment than jewellery. I prefer that combination here, particularly with orange doing the work of separating the hands from their background.

Orange hands, green scale, less writing

Moving in from the bezel, the ceramic insert carries orange elapsed-time markings on its inner scale and green depth markings on the outside, with the no-decompression scale expressed in feet. That choice of units belongs to this edition, even though we would normally reach for metres. The colours also establish a clear visual order in the photographs: orange catches the eye first, while green settles into the surrounding dial. It is a busy ring around a comparatively quiet centre, which makes the decision to remove most of the dial lettering count.

Belmont uses applied black indices and oversized orange hands against that textured kelp green, with DOXA as the only brand name on the dial. The date remains at three o'clock, so the restraint is about typography rather than removing everyday information. In the close-ups, the green surface has the granular look of painted metal rather than a smooth pool of colour, and the black surrounds give the pale marker centres a firm edge. I would keep the date; this dial has room for something useful. Less writing, not less watch.

Coronado on the back, rice links on the wrist

Turn it over and the collaboration becomes more explicit, with Coronado Island on the custom caseback alongside DOXA SUB FROGGER lettering and individual limited-edition markings. Inside is a Swiss mechanical automatic movement displaying hours, minutes, seconds and the date. The solid back makes the engraving, rather than movement decoration, the thing to look at on this side. That division feels sensible to me: the front is concerned with reading the time, while the reverse gives the owner the local reference that explains why the collaboration exists.

The stainless-steel beads-of-rice bracelet is sandblasted to match the case, closing with a folding clasp and ratcheting wetsuit extension. Belmont also supplies a green nylon NATO strap with sandblasted hardware, and the 20 mm lug width leaves a familiar size for anyone who wants another option. Those are two quite different visual directions within the same package: the bracelet continues the grey metal around the wrist, while the nylon gives the green more space. Neither asks for a polished buckle to interrupt the finish chosen for the watch head.

The detail I keep returning to is the absence of Belmont's name on the dial. A retailer collaboration has an obvious opportunity to advertise the retailer, yet this one lets a recognisable combination of surfaces and colours serve that purpose instead. Whether the naval tribute means anything to you is a separate question; I think the design is more persuasive because it does not require that connection. The caseback can carry the story for its owner, and everyone else gets a clear view of the watch.

DOXA × Belmont SUB 300 Beta Frogger pricing and availability

The DOXA × Belmont SUB 300 Beta Frogger, reference 830.10.101.10-SE10, is offered through Belmont Watches as a numbered limited edition. The package includes the sandblasted steel beads-of-rice bracelet, green nylon NATO strap, custom outer box and green inner presentation box. The US list price is US$2,890; Australian storefront pricing is approximately A$4,100 and can vary with the storefront's currency conversion. Both figures are for the bracelet-and-NATO package, rather than separate strap versions, and Belmont also lists a rubber strap as an additional purchase.