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Bremont Supermarine S300 40mm Stainless Steel
Ref. S300-WH-R-S
The Supermarine line was built around British naval heritage and a conviction that a serious dive watch need not be a large one. The 40mm S300 makes that argument clearly: at 13mm thick it wears considerably flatter than the 43mm siblings in the same family, and while the 49mm lug-to-lug measurement runs slightly longer than is typical at this diameter, the result on the wrist is a watch that feels purposeful without being assertive. The dial is worth attention in changing light. The matte white surface is broken at its centre by a raised hobnail-textured section, which catches the light differently from the surrounding field and gives the dial a quiet visual depth the flat reading of "white dial" does not suggest. The navy blue ceramic bezel is DLC-treated at the case barrel through Bremont's Trip-Tick three-piece construction, meaning the most contact-prone surfaces resist daily abrasion better than standard steel. The COSC-certified BE-92AE, built on the ETA 2892 base, keeps the movement case as thin as it is while delivering the precision rating that accompanies a chronometer certificate.
- Reference
- S300-WH-R-S
- Brand
- Bremont
- Collection
- Supermarine
- Case size
- 40mm
- Case thickness
- 13mm
- Lug width
- 20mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- White
- Crystal
- Sapphire
- Bezel
- Unidirectional rotating
- Movement
- Automatic
- Calibre
- ETA 2892
- Functions
- Date
- Water resistance
- 300m
- Bracelet / strap
- Rubber strap
- Strap colour
- Blue
- Clasp
- Buckle
- Lume
- Super-LumiNova
- Condition
- Pre-owned
- Retailer
- Mappin & Webb
Additional specifications
- Lug-to-lug
- 49mm
- Power reserve
- 38 hours
Learn more about Bremont
Nick and Giles English founded Bremont in 2002, four years after their father died in a plane crash that Nick survived. All three had restored and flown vintage aircraft together, and the brand that emerged is inseparable from that. The name comes from Antoine Bremont, a French farmer who sheltered the brothers after an emergency landing.
Bremont set out to rebuild British watchmaking, which had effectively ended in the twentieth century. The early watches used Swiss movements in British-designed cases, with the Trip-Tick three-part case construction and a hardened outer barrel treated to over 2000 Vickers.
The military and aviation work is real rather than thematic. Bremont holds contracts with squadrons across the RAF, the US Air Force, and other services, producing issued watches for specific units, and has made watches for Martin-Baker ejection seat survivors — tested to the ejection forces themselves.
The company has also built watches incorporating material from historical objects: oak and copper from HMS Victory, aluminium from the Wright Flyer, and steel from Bletchley Park.
The manufacturing ambition advanced with the opening of a facility in Henley and the release of the ENG300 series in 2021, the first Bremont movement designed and largely made in England. Production is in the low tens of thousands annually.
- 2002
- Nick and Giles English found Bremont.
- 2007
- The first watches ship with the Trip-Tick case.
- 2009
- The Martin-Baker collaboration begins.
- 2021
- The ENG300 becomes the first English-made Bremont calibre.
Also in 6 collections
This watch appears in Stainless Steel Watches (2,624), Back in Stock (1,916), Automatic Watches (1,472), Sports Watches (676), Dive Watches (481) and Pre-Owned, Ex-Display & Vintage Watches (262).
What the specifications mean
A mechanical watch built to be worn hard and got wet.
Strengths
- 300m water resistance, rated for actual diving
- 40mm suits most wrists
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
Worth knowing
- 38-hour reserve means winding it after a day off
Bremont Supermarine S300 alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | S300-WH-R-S | L37744602 | R32145158 |
|---|---|---|---|
| Price | £2,350 | £2,050 | £2,150 |
| Case size | 40mm | 42mm | 43mm |
| Water resistance | 300m | 300m | 300m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Rubber strap | Leather strap | Stainless steel bracelet |
| Power reserve | 38 hours | 72 hours | 59 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 300m it is rated for swimming, snorkelling and recreational diving.
Will the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Does it need a battery?
No. It is automatic — the motion of your wrist winds it, and there is no cell to replace.
How long does it run for when it's not worn?
About 38 hours fully wound — so it will usually stop if you leave it off overnight.
What size strap does it take?
20mm. Any strap of that width will fit, and on most modern watches quick-release bars make the swap a two-minute job with no tools.
Will it fit my wrist?
Lug-to-lug is 49mm, which suits wrists from roughly 16.5cm (6½ inches) upward.
Lug-to-lug decides fit more than case diameter does.
Is it a men's or women's watch?
Listed as men's, though at 40mm it sits in the range that suits anyone.
Cheapest place to buy
Mappin & Webb at £2,350, pre-owned. No UK retailer we track lists this reference new.
Is this available new?
Not from the UK retailers we track. This reference is listed as pre-owned only, at £2,350 from Mappin & Webb. A pre-owned watch has been worn, and is normally sold under the retailer’s own warranty rather than the manufacturer’s.
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