Longines HydroConquest Hydroconquest Chronograph Tachymeter

Reference L3.651.4.16.6

About this watch

The Longines HydroConquest L3.651.4.16.6 is a robust and stylish diver's watch that combines performance with elegance. Its 41mm stainless steel case features a rotating bezel, marked from 0 to 60, for precise timing underwater. The sapphire crystal glass is scratch-resistant and adds to the watch's durability. A closed case back limits visibility of the movement but adds to the watch's sturdiness. With a lug width of 21mm, the Hydroconquest comes with a well-crafted stainless steel bracelet that feels solid yet comfortable on the wrist. The chronograph feature is a highlight, providing additional functionality for timing events. The date function ensures you're always on top of your schedule. Whether diving or just out for a casual lunch, this watch feels right at home. Its impressive 300m water resistance makes it a reliable companion for underwater adventures. With a reliable and accurate automatic movement, the Hydroconquest keeps time with impressive accuracy. A power reserve of 42 hours ensures you can take it off for a day or two without worrying about winding it again. The Longines HydroConquest is more than just a watch; it's a statement piece that combines performance with elegance.
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Key Features

  • Longines caliber L667 automatic movement
  • 41mm stainless steel case with rotating bezel
  • Sapphire crystal glass for scratch-resistance and durability
  • 300m water resistance for underwater adventures
  • Chronograph feature for timing events
  • Date function for scheduling
  • 42-hour power reserve for reliability

Specifications

Brand
Longines
Family
HydroConquest
Model
Hydroconquest Chronograph Tachymeter
Reference
L3.651.4.16.6
Movement
l667
Movement Features
  • Hours, Minutes, Small Seconds
  • Date
  • Chronograph
Case
Stainless Steel 41mm
Dial Color
White
Crystal
Sapphire
Water Resistance
300

Current Listings

[WTS] Longines HydroConquest 43mm Automatic – Black Dial – Full Kit – $1,095

Longines HydroConquest 43mm Automatic – Black Dial – Full Kit – $1,095

Longines - L3.782.4 · $1,095
This Longines HydroConquest automatic watch features a black dial and 43mm case size, which provides a strong wrist presence.

  • Condition: very good
  • Case size: 43mm diameter
  • Case wear: normal wear consistent with careful use
Posted at
Feb 18, 2026, 4:40 PM
Active
[WTS] Longines Hydroconquest 41m Green full kit with OEM bracelet and rubber strap

Longines Hydroconquest 41m Green full kit with OEM bracelet and rubber strap

A green ceramic automatic watch from Longines, part of the Hydroconquest series, featuring a Swiss movement with 72-hour power reserve.

  • Condition: Used with signs of wear
  • Case diameter: 41 mm
  • Water resistance: 300m / 30 bar
  • Movement: Longines Calibre L888 series with 72hr power reserve
Posted at
Feb 16, 2026, 4:12 PM
Active
[WTS] Longines Hydroconquest 41mm Blue - $850

Longines Hydroconquest 41mm Blue - $850

Longines - L37424966 · $850
A Longines Hydroconquest 41mm automatic diver features a blue sunburst dial, matching blue ceramic bezel and has excellent timekeeping capabilities.

  • Condition: Excellent with light signs of wear
  • Case size: 41mm diameter
  • Bezel material: Ceramic
  • Bracelet condition: Light scuffs on the clasp
Posted at
Feb 11, 2026, 1:00 PM
Active
[WTS] 2024 Longines HydroConquest 43mm Black Ceramic L3.782.4

2024 Longines HydroConquest 43mm Black Ceramic L3.782.4

Longines - L3.782.4 · $999
2024 Longines HydroConquest watch with 43mm black ceramic case.

  • Case material: black ceramic
  • Size: 43mm diameter
Posted at
Feb 8, 2026, 1:07 PM
Active
[WTS] Longines Hydroconquest 41m Green full kit with OEM bracelet and rubber strap

Longines Hydroconquest 41m Green full kit with OEM bracelet and rubber strap

For sale is my Longines Hydroconquest 41m ceramic automatic in green. It's a stainless steel case with ceramic bezel and Swiss automatic movement (Longines Calibre L888 series) with approx. 72 hr power reserve.

  • Condition: Used
  • Case Size: 41 mm diameter
  • Case Material: Stainless steel case
  • Movement: Longines Calibre L888 series, approx. 72 hr power reserve
Posted at
Feb 6, 2026, 9:31 AM
Active
[WTS] Longines HydroConquest (Ref. L3.782.4.96.6) $975

Longines HydroConquest (Ref. L3.782.4.96.6) $975

The Longines HydroConquest is a 43mm Swiss automatic diver’s watch featuring a sunray blue dial and 300 meter water resistance.

  • Condition: Very good pre-owned
  • Diameter: 43mm
  • Water Resistance: 300m depth rating
  • Movement: L888 caliber
Posted at
Feb 4, 2026, 11:11 PM
Active
Longines HydroConquest, L3.781.4.06.9, Steel Diver, Olive, Excellent Condition.

Longines HydroConquest, L3.781.4.06.9, Steel Diver, Olive, Excellent Condition.

Longines - L3.781.4.06.9 · $1,095
This Longines HydroConquest is a steel diver's watch with an olive green matte dial and a unidirectional rotating ceramic bezel. The stainless steel case measures 41mm in diameter and has a water resistance of up to 300 meters.

  • Condition: Excellent Condition
  • Case Diameter: 41mm
  • Thickness: 11.9mm
  • Bezel Type: Unidirectional rotating Green Ceramic
Posted at
Feb 5, 2025, 2:47 AM
Active