Longines HydroConquest Hydroconquest Automatic 42 Stainless Steel / Black / Bracelet

Reference L3.788.4.56.6

Longines Hydroconquest Automatic 42 Stainless Steel / Black / Bracelet

About this watch

The Longines HydroConquest L3.788.4.56.6 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 measures 42 mm in diameter and is equipped with a screw-in crown and a unidirectional rotating bezel fitted with a 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 L3.788.4.56.6 is fitted with a stainless steel bracelet secured by a double security folding clasp with a micro-adjustment system.

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Specifications

Brand

Longines

Family

HydroConquest

Model

Hydroconquest Automatic 42 Stainless Steel / Black / Bracelet

Reference

L3.788.4.56.6

Movement

l888-2

Movement Features

Hours, Minutes, Seconds
Date

Case

42mm

Dial Color

Black

Crystal

Sapphire

Water Resistance

300

Current Listings

[US] 2026 Longines HydroConquest 39 mm Blue $1,950

Longines - HydroConquest 39 mm Blue · $1,950

2026 Longines HydroConquest 39 mm Blue for sale, a great watch and arguably the best watch released this year. It comes as a full set with active warranty card, booklets, inner box, outer box, etc.

Condition: Like new, great condition
Water Resistance: 100m water resistance

Posted at

May 27, 2026, 12:06 PM

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Longines HydroConquest 42mm

Longines - L3.788.4.96.6 · $1,900

This listing is for a brand new Longines HydroConquest 42mm blue dial watch, featuring a ceramic bezel and quick micro adjust bracelet.

Condition: Brand New In Box (BNIB)
Diameter: 42mm
Material: ceramic and lacquered

Posted at

May 26, 2026, 3:35 PM

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Longines Hydroconquest 43mm -Like New

Longines - L3.782.4.56.6 · $1,180

This Longines Hydroconquest is a 43mm watch with a black dial, purchased new in April and still in fantastic condition.

Condition: Like New
Case size: 43mm
Lug to lug length: 53
Thickness: 11.90mm

Posted at

May 25, 2026, 6:20 PM

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Longines Hydroconquest 41mm - Black Dial

Longines - L3.781.4.56.6 · $975

A Longines Hydroconquest 41mm Automatic watch with a black dial, stainless steel case, and ceramic bezel.

Condition: Good condition, minor scratches/scuffs in sapphire and minimal wear marks on bracelet and clasp
Case size: 41mm diameter
Bezel material: stainless steel and ceramic
Bracelet type: original bracelet (and links)

Posted at

May 24, 2026, 3:31 PM

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Longines Hydroconquest Chronograph 41 Ref. L3.783.4 – Travel Box & Manual | $1,750

Longines - L3.783.4 · $1,750

The Longines Hydroconquest Chronograph 41 is a high-performance Swiss diver's watch featuring a blue ceramic bezel and screw-down crown, powered by the L688.2 column-wheel chronograph movement with a 54-hour power reserve.

Condition: Very good with minor usage marks
Movement: Longines L688.2, automatic column wheel chronograph with 27 jewels, 28,800 bph, and a 54-hour power reserve
Case size: 41mm diameter
Thickness: 15.6mm

Posted at

May 24, 2026, 12:47 PM

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Longines Hydroconquest 43mm

Longines - L3.782.4.56.6 · $1,240

The watch is a Longines Hydroconquest model L3.782.4.56.6 with a black dial and a 43mm case size.

Condition: Brand new with minor use (about a month)
Case size: 43mm diameter
Lug to lug length: 53mm
Thickness: 11.90mm

Posted at

May 22, 2026, 4:14 PM

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(brand new) Longines HydroConquest 39mm - $1700 shipped

Longines - HydroConquest · $1,700

This brand new Longines HydroConquest features a 39mm stainless steel case with black dial and ceramic bezel insert, along with a date display at the 3 o'clock position.

Condition: Unworn
Case material: stainless steel
Bracelet material: stainless steel
Water resistance: 300m

Posted at

May 21, 2026, 8:02 PM

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