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Doxa SUB 300T 42.50mm X 44.50mm Mens Watch
Ref. 840.10.131.10
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Stepping up in Doxa's range
The SUB 300T Conquistador of 1968 was a pivotal watch: the first diver made for the general public to carry a helium escape valve, a piece of engineering that the professional dive community had kept to itself until Doxa changed the terms. The 2019 revival honours that lineage directly rather than simply borrowing the name, carrying forward the cushion case shape and the integrated decompression calculator on the bezel alongside the rated depth — 1,200 metres — that leaves most divers' watches looking cautious by comparison. The Sea Emerald dial is a sunray green, which means it shifts between deep and pale depending on the angle and the light, and the full commitment to lume across every dive-relevant element — indices, bezel insert, hands — gives it a coherent logic underwater that the surface appearance hints at. On the wrist the cushion case sits differently from a conventional round, pulling the weight in toward the centre of the wrist rather than spreading it wide, and the steel bracelet is properly proportioned to the lug width rather than the afterthought it can be on watches rated to lesser depths.
- Reference
- 840.10.131.10
- Brand
- Doxa
- Case size
- 44.5mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Green
- Crystal
- Sapphire
- Bezel
- Unidirectional rotating
- Movement
- Automatic
- Calibre
- SW200
- Water resistance
- 200m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Lume
- Super-LumiNova
- Retailer
- Mappin & Webb
Learn more about Doxa
Doxa was founded by Georges Ducommun in Le Locle in 1889, and spent its early decades on pocket watches and, notably, dashboard clocks for the emerging car industry — supplying Bugatti among others.
Its lasting contribution came much later. In 1967 Doxa released the SUB 300, developed in consultation with professional divers, and it introduced several things now taken for granted. The dial was orange, chosen after testing which colour remained visible longest as depth filtered out light. The bezel carried a US Navy no-decompression scale rather than simple minute markers, letting a diver read safe bottom time directly. The beads-of-rice bracelet included an expansion section to fit over a wetsuit.
Jacques Cousteau's organisation distributed the watches, and US Divers sold them in America. The SUB became genuine professional equipment rather than a dive-styled dress watch, and it appears throughout Clive Cussler's novels on the wrist of Dirk Pitt.
Doxa struggled through the quartz era and was largely dormant before being revived by the Jenny family, who reissued the SUB faithfully from 2002 onward.
The modern range remains almost entirely dive watches, with the same cushion case, the same bezel scale, and dial colours named for their depth-rating heritage — Professional orange, Sharkhunter black, Searambler silver, Caribbean blue.
- 1889
- Georges Ducommun founds Doxa in Le Locle.
- 1908
- Supplies dashboard clocks to early car manufacturers.
- 1967
- The SUB 300 debuts with an orange dial and decompression bezel.
- 2002
- The SUB is reissued under new ownership.
Also in 6 collections
This watch appears in Back in Stock (4,528), Stainless Steel Watches (3,001), Automatic Watches (1,693), Watches 44mm and Over (759), Sports Watches (746) and Dive Watches (528).
Temporarily out of stock
Mappin & Webb is not currently taking orders for this reference. Last listed as available on 21 October 2026. Stock is checked nightly and this page updates when it returns.
What the specifications mean
A mechanical watch built to be worn hard and got wet.
Strengths
- 200m water resistance, rated for actual diving
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
Worth knowing
- 44.5mm sits at the larger end
Doxa SUB 300T alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | 840.10.131.10 | ZO9590 | 01 743 7734 4197-SET |
|---|---|---|---|
| Price | £1,890 | £1,799 | £1,785 |
| Case size | 44.5mm | 41mm | 43.5mm |
| Water resistance | 200m | 200m | 300m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Rubber strap | Stainless steel bracelet |
| Power reserve | — | 44 hours | 41 hours |
| This watch |
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Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Yes. At 200m it is rated for swimming, snorkelling and recreational diving.
Water resistance explainedWill the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Sapphire, mineral and acrylic comparedDoes it need a battery?
No. It is automatic — the motion of your wrist winds it, and there is no cell to replace.
Quartz, automatic and solar comparedIs it a men's or women's watch?
Listed as men's.
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