Longines HydroConquest Hydroconquest Automatic 39 Stainless Steel / Black / Mesh

Reference L3.779.4.90.6

About this watch

The Longines HydroConquest L3.779.4.90.6 debuted in 2026 as part of the HydroConquest collection, Longines’ line of contemporary dive watches designed for professional water resistance and everyday durability. The model follows the design direction introduced with the HydroConquest GMT in 2024, which revised the collection’s dial layout and finishing. The round stainless steel case is equipped with a screw-in crown and a unidirectional rotating bezel fitted with a blue ceramic insert. Water resistance is rated to 30 bar. The watch is fitted with a scratch-resistant sapphire crystal with several layers of anti-reflective coating applied to both sides. The dial is finished in black with a polished lacquered surface. Applied indexes serve as hour markers, reflecting the updated HydroConquest design that no longer features Arabic numerals on the dial. Silvered polished hands indicate the time, while a date display completes the functional layout. Power is provided by the Longines calibre L888, a self-winding mechanical movement beating at 25,200 vibrations per hour. The movement is equipped with a monocrystalline silicon balance spring and offers a power reserve of approximately 72 hours. It drives the central hours, minutes, and seconds together with the date indication. The L3.779.4.90.6 is fitted with a stainless steel bracelet in a Milanese mesh style, secured by a double security folding clasp with a micro-adjustment system.
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Specifications

Brand
Longines
Family
HydroConquest
Model
Hydroconquest Automatic 39 Stainless Steel / Black / Mesh
Reference
L3.779.4.90.6
Movement
l888-2
Movement Features
  • Hours, Minutes, Seconds
  • Date
Case
39mm
Dial Color
Black
Crystal
Sapphire
Water Resistance
300

Current Listings

[WTS] Longines HydroConquest GMT 41mm Black, Full Kit, June 2025

Longines HydroConquest GMT 41mm Black, Full Kit, June 2025

Up for sale is my mint condition Longines HydroConquest GMT, a full kit with box, papers, tags, and over 4 years left on the factory warranty.

  • Condition: Mint condition
  • Case dimensions: 41mm diameter, 49mm lug to lug, 12.9mm thickness
  • Movement: L844.5 with 72hrs power reserve
  • Water resistance: 300m
Posted at
Apr 19, 2026, 10:47 PM
Active
[WTS] Longines Hydroconquest 39mm Black MINT

Longines Hydroconquest 39mm Black MINT

A mint condition Longines Hydroconquest 39mm in black with a super comfortable bracelet and excellent bezel action.

  • Condition: MINT
  • Bracelet type: Super comfortable bracelet
  • Clasp type: Excellent on the fly clasp
  • Bezel action: Great bezel action
Posted at
Apr 19, 2026, 9:12 AM
Active
[WTS] Longines HydroConquest 39mm Green Ceramic Bezel 2026 NEW L3.779.4.06.6 – $2800 + shipping

Longines HydroConquest 39mm Green Ceramic Bezel 2026 NEW L3.779.4.06.6 – $2800 + shipping

Longines - L3.779.4.06.6 · $2,800
This Longines HydroConquest features a stunning green ceramic bezel and matching dial, with a 39mm size that wears well on the wrist.

  • Condition: Brand new
  • Case Size: 39mm diameter
  • Bezel Material: green ceramic
Posted at
Apr 17, 2026, 6:00 AM
Active
[WTS] 2026 Longines Hydroconquest 39mm - Grey Bezel / Black Dial

2026 Longines Hydroconquest 39mm - Grey Bezel / Black Dial

Longines - L3-779-4-70-6 · $2,100
This 2026 Longines Hydroconquest is a 39mm grey bezel/black dial watch, purchased directly from Longines and regularly worn. It's free of major scratches or dents but has minor wear on the back of one lug.

  • Condition: Excellent to LNIB (like new in box)
  • Bracelet length: up to an 8in wrist
  • Bent link pin: one link pin is bent and unusable
  • Included accessories: all original packaging, accessories, and paperwork
Posted at
Apr 16, 2026, 3:09 PM
Active
[WTS] Longines HydroConquest Sunray Blue- L3.790.4.96.6

Longines HydroConquest Sunray Blue- L3.790.4.96.6

Longines - L3.790.4.96.6 · $2,900
A brand new Longines HydroConquest with sunray blue dial, featuring a new box and papers.

  • Condition: Brand new
  • Box And Papers: brand new
Posted at
Apr 16, 2026, 12:11 PM
Active
[WTS] Longines HydroConquest GMT - Unworn, Full Set, Black Dial 41mm. The watch is in completely unworn condition and comes as a full set including box, papers, and all original accessories. Price:1700. UK-based. Happy to ship or meet depending on location. Dm if interested

Longines HydroConquest GMT - Unworn, Full Set, Black Dial 41mm. The watch is in completely unworn condition and comes as a full set including box, papers, and all original accessories. Price:1700. UK-based. Happy to ship or meet depending on location. Dm if interested

The Longines HydroConquest GMT is a 41mm timepiece that comes as a full set including box, papers, and all original accessories. It is in completely unworn condition.

  • Condition: Unworn
  • Case Size: 41mm
  • Set: Full set including box, papers, and all original accessories
Posted at
Apr 16, 2026, 11:26 AM
Active
[WTS] Longines Hydroconquest GMT 41mm Black (Nov 2024)- $2950 AUD (Sydney, Australia)

Longines Hydroconquest GMT 41mm Black (Nov 2024)- $2950 AUD (Sydney, Australia)

Longines - L3.826.4.53.2 · $2,950
a black Longines Hydroconquest GMT watch with a 41mm case size.

  • Material: Stainless Steel
  • Diameter: 41mm
  • Depth rating: 300m
Posted at
Apr 16, 2026, 9:54 AM
Active
[WTS] Longines HydroConquest 41mm

Longines HydroConquest 41mm

Longines - L3.781.4.96.6 · $1,100
A Longines HydroConquest 41mm watch with a blue sunburst dial, featuring a clean crystal and flawless dial.

  • Condition: Excellent pre-owned condition
  • Diameter: 41mm
Posted at
Apr 15, 2026, 3:43 PM
Active
[WTS] Longines Hydroconquest Chronograph 41 Ref. L3.783.4 – Travel Box & Manual | $1,900

Longines Hydroconquest Chronograph 41 Ref. L3.783.4 – Travel Box & Manual | $1,900

Longines - L3.783.4 · $1,900
This Longines Hydroconquest Chronograph is a high-performance Swiss diver's watch featuring a blue ceramic bezel and screw-down crown, powered by the calibre L688.2 column-wheel chronograph movement with a 54-hour power reserve.

  • Condition: Very good with minor usage marks
  • Case Size: 41mm x 51mm stainless steel case, 15.6mm thickness, 21mm lug width
  • Movement: Longines L688.2 automatic column wheel chronograph with 27 jewels, 28,800 bph, and a 54-hour power reserve
  • Water Resistance: 300m (30 ATM)
Posted at
Apr 15, 2026, 11:30 AM
Active