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Longines HydroConquest 41mm Stainless Steel
Ref. L3.781.4.05.9
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Stepping up in Longines's range
Released exclusively for the Watches of Switzerland Group, this HydroConquest pairs a sunray slate-grey dial with a matte green ceramic bezel insert — a combination that does not appear anywhere else in the standard HydroConquest range. The green NATO strap and link-removal tool included in the presentation set confirm that this was conceived as a collector's piece from the outset, not a standard reference with an afterthought finish. At 51.1mm lug to lug, the footprint is generous, but tightly curved lugs keep it pulled against the wrist rather than bridging it, and 11.9mm of thickness means it clears a cuff without protest — unusually composed proportions for a diver rated to 300m. The unidirectional ceramic bezel reads cleanly against the grey dial in direct light; in low light, the Super-LumiNova takes over with the kind of coverage a watch at this depth rating needs to justify. The L888.2 runs on a silicon balance-spring at a deliberately unhurried 25,200vph, a choice that trades raw frequency for a 72-hour power reserve and long-term resilience against magnetic interference. The bracelet's integrated diving extension handles a wetsuit cuff without tools, and the double-safety folding clasp closes with the solidity you would hope for at depth.
- Reference
- L3.781.4.05.9
- Brand
- Longines
- Collection
- HydroConquest
- Case size
- 41mm
- Case thickness
- 11.9mm
- Lug width
- 21mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Grey
- Crystal
- Sapphire
- Bezel
- Unidirectional rotating
- Movement
- Automatic
- Calibre
- ETA A31.L01
- Functions
- Date
- Water resistance
- 300m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Clasp
- Folding clasp
- Lume
- Luminous
- Condition
- Pre-owned
- Retailer
- Mappin & Webb
Additional specifications
- Lug-to-lug
- 51.1mm
- Power reserve
- 72 hours
- Origin
- Swiss made
Learn more about Longines
Auguste Agassiz began trading watches in Saint-Imier in 1832, but the modern company dates from 1860, when his nephew Ernest Francillon built a factory in the meadows beside the Suze — the longines of the local dialect — and consolidated the scattered outworkers of the region under one roof.
Longines registered its winged hourglass in 1889. It is the oldest watch trademark still in continuous use.
The company's identity was built on precision and on timing things in public. It supplied chronographs for the first modern Olympic events it timed in 1896, timed the 1912 Federal Gymnastics Festival with a broken-wire mechanism accurate to a hundredth of a second, and developed the photo-finish camera and the quartz timing devices used across twentieth-century athletics.
Its aviation associations are equally deep. Longines instruments were carried by Charles Lindbergh across the Atlantic in 1927, and the Hour Angle watch, designed to Lindbergh's own specification to simplify longitude calculation, remains in the catalogue. Amelia Earhart and Howard Hughes both navigated by Longines.
The house was among the most decorated at nineteenth-century observatory trials, holding numerous precision records. Since joining the Swatch Group in 1983 it has occupied the accessible-heritage position: exclusive ETA-based movements, archive-driven designs through the Heritage line, and volume that makes it one of the group's most important brands.
- 1860
- Ernest Francillon builds the factory at Les Longines.
- 1889
- The winged hourglass is registered — the oldest watch trademark in use.
- 1912
- Broken-wire timing achieves hundredth-second accuracy.
- 1927
- Lindbergh crosses the Atlantic with Longines instruments.
- 1983
- Becomes part of the Swatch Group.
Also in 7 collections
This watch appears in the Longines HydroConquest range (42), Back in Stock (4,405), Stainless Steel Watches (2,927), Automatic Watches (1,634), Sports Watches (729), Dive Watches (521) and Pre-Owned, Ex-Display & Vintage Watches (326).
Temporarily out of stock
Mappin & Webb is not currently taking orders for this reference. Last listed as available on 25 September 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
- 300m water resistance, rated for actual diving
- Sapphire crystal, which resists scratching
- 72-hour reserve survives a weekend off the wrist
- Luminous hands and markers for low light
- Sits in the lower half of Longines's range as we list it
Longines HydroConquest alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | L3.781.4.05.9 | R32105203 | 01 400 7763 4157 |
|---|---|---|---|
| Price | £1,550 | £2,200 | £2,050 |
| Case size | 41mm | 42mm | 43.5mm |
| Water resistance | 300m | 300m | 300m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Stainless steel bracelet | Stainless steel bracelet |
| Power reserve | 72 hours | 80 hours | 120 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.
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 comparedHow long does it run for when it's not worn?
About 72 hours fully wound — enough to sit off the wrist over a weekend and still be running.
What size strap does it take?
21mm. 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 51.1mm, which suits wrists from roughly 17.5cm (7 inches) upward.
Lug-to-lug decides fit more than case diameter does.
How to size a watch to your wristIs it a men's or women's watch?
Listed as men's.
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