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Longines HydroConquest 41mm Mens Watch Green
Ref. L37904062
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Stepping up in the same colour and case shape
The HydroConquest has been Longines' serious diver since 2007, but this reference marks a genuine turning point: the first time the line has carried a dedicated mechanical GMT. The movement behind it is the L844.4, a flyer GMT derived from the ETA A31.L011 platform, which means the local hand adjusts independently in one-hour steps without stopping the seconds — the correct way to handle a time zone change in transit. A silicon balance spring and a 72-hour reserve make it a practical travel companion rather than an occasional one. What Longines has done with the dial is worth noting. Standard HydroConquest models lean on oversized Arabic numerals; this one swaps them for round and baton indices, which gives the green dial a cleaner read and suits the GMT complication better than a busier layout would. The ceramic bezel insert is polished rather than matte, which catches light differently from the dial and stops the watch reading as flat. At 49.4mm lug to lug, it sits shorter on the wrist than the older 41mm HydroConquests, and at 12.9mm it wears closer than the rating might suggest — a 300m diver that tucks under a cuff without protest.
- Reference
- L37904062
- Brand
- Longines
- Collection
- HydroConquest
- Case size
- 41mm
- Case thickness
- 12.9mm
- Lug width
- 21mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Green
- Crystal
- Sapphire
- Bezel
- Rotating
- Movement
- Automatic
- Calibre
- ETA A31.L011
- Functions
- GMT, Date
- Water resistance
- 300m
- Bracelet / strap
- Fabric strap
- Strap colour
- Green
- Clasp
- Buckle
- Lume
- Luminous
- Retailer
- Goldsmiths
Additional specifications
- Lug-to-lug
- 49.4mm
- Power reserve
- 72 hours
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 (3,734), Stainless Steel Watches (2,581), Automatic Watches (1,570), Sports Watches (707), Dive Watches (505) and Green Dial Watches (343).
Temporarily out of stock
Mappin & Webb is not currently taking orders for this reference. Last listed as available on 19 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
- Second time zone for travelling
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 | L37904062 | R32138208 | 821.10.101.10 |
|---|---|---|---|
| Price | £2,550 | £2,500 | £2,590 |
| Case size | 41mm | 42mm | 42.5mm |
| Water resistance | 300m | 300m | 300m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Fabric strap | Stainless steel bracelet | Stainless steel bracelet |
| Power reserve | 72 hours | 80 hours | 38 hours |
| This watch | Closely matched |
|
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 49.4mm, which suits wrists from roughly 16.5cm (6½ 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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