Longines HydroConquest Hydroconquest Automatic 42 Stainless Steel / Black / Mesh

Reference L3.788.4.90.6

Longines Hydroconquest Automatic 42 Stainless Steel / Black / Mesh

About this watch

The Longines HydroConquest L3.788.4.90.6 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 measures 42 mm in diameter and 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 L3.788.4.90.6 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 42 Stainless Steel / Black / Mesh

Reference

L3.788.4.90.6

Movement

l888-2

Movement Features

Hours, Minutes, Seconds
Date

Case

42mm

Dial Color

Black

Crystal

Sapphire

Water Resistance

300

Current Listings

2026 Longines HydroConquest L37884906 42 mm Black Dial Blue Bezel Full Set $1,900

Longines - L37884906 · $1,900

The Longines HydroConquest L37884906 features a black dial and blue ceramic bezel, with an automatic movement providing reliable performance. The watch has a robust build, unidirectional dive bezel, and strong water resistance, making it a capable tool watch while maintaining a refined aesthetic.

Condition: Excellent (pre-owned, minimal wear)
Year: 2026
Case size: 42mm diameter
Case material: Stainless steel

Posted at

Apr 30, 2026, 10:26 PM

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2026 Longines HydroConquest 39mm - Black Ceramic - Newest Release - Full Set

Longines - L3.779.4.56.6 · $1,900

The newly redesigned Longines HydroConquest in the highly sought-after 39mm size, featuring a refined dial and upgraded bracelet.

Condition: Excellent Used Condition
Size: 39mm diameter
Thickness: ~11.9mm
Lug-to-lug length: 47mm

Posted at

May 7, 2026, 8:43 PM

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Longines Hydroconquest GMT 41mm

Longines - Hydroconquest GMT 41mm · $1,875

A black dial Longines Hydroconquest GMT watch with a 41mm case size, comes complete with a full set including a dated warranty card.

Condition: Pre-owned, minor signs of wear
Diameter: 41mm
Case material: unknown
Band: no details provided

Posted at

May 7, 2026, 3:36 PM

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Longines Hydroconquest 43mm L3.782.4.56.6-3 weeks owned.

Longines - L3.782.4.56.6 · $1,350

A Longines Hydroconquest 43mm watch on a black dial with a stainless steel bracelet, now on an Ali Rubber strap.

Condition: Mint condition, worn approximately 5 times
Case size: 43mm diameter
Lug to lug: 53mm
Thickness: 11.90mm

Posted at

May 7, 2026, 4:43 AM

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Longines Hydroconquest Quartz Two Tone L3.740.3.56.7 - $600 🚢

Longines - L3.740.3.56.7 · $600

This Longines Hydroconquest is a 41mm two-tone diver's watch with a quartz movement.

Condition: Used with light scratches
Size: 41mm diameter

Posted at

May 6, 2026, 9:43 PM

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2025 Longines Hydroconquest 41mm Ref: L37814056

Longines - L37814056 · $1,300

This listing is for a 2025 Longines Hydroconquest 41mm watch, featuring an automatic self-winding caliber L888.5, unidirectional green ceramic bezel, and 300M water resistance.

Condition: Like new with some minor marks on the bracelet and buckle
Case size: 41mm
Bracelet type: Stainless steel
Water resistance: 300m depth rating

Posted at

May 6, 2026, 8:37 PM

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Longines Hydroconquest 42 mm “Green” 2026

Longines - Hydroconquest 42mm · $1,800

Up for sale is one of my new Longines Hydroconquest 42mm watches, I purchased several but find myself gravitating towards other models.

Condition: New
Case size: 42mm diameter

Posted at

May 6, 2026, 7:28 PM

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(Longines) (2026 Hydroconquest 39mm Commonwealth) Brand New and Unworn

Longines - L3.779.4.09.9 · $2,650

This is a Limited Edition Hydroconquest Commonwealth Games watch from Longines, purchased brand new from an authorized dealer and still under warranty.

Case diameter: 39mm
Box condition: great condition with exception of price sticker on outer box

Posted at

May 6, 2026, 5:30 PM

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Longines HydroConquest 39mm Black Dial – 2026 Model, Worn Once. $1,995

Longines - HydroConquest 2026 Model · $1,995

A Longines HydroConquest with a black dial and steel bracelet for sale. It's the latest iteration from 2026, purchased recently but only worn once to a wedding.

Condition: Near mint, worn once
Case size: 39mm
Movement: Automatic

Posted at

May 4, 2026, 12:18 PM

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