Longines HydroConquest Hydroconquest Chronograph Tachymeter Black

Reference L3.651.4.56.6

About this watch

The Longines HydroConquest Chronograph Tachymeter Black is a testament to the brand's dedication to creating timepieces that combine functionality, style, and durability. Its striking black dial exudes a sporty yet sophisticated vibe, making it a versatile option for both casual outings and formal events. The watch features a robust movement based on the ETA/Valjoux 7750, boasting a 42-hour power reserve and a frequency of 28,800 vibrations per hour. With its impressive water resistance of 300 meters and sapphire glass protection, this watch is designed to withstand underwater activities while remaining stylish enough for everyday wear. The stainless steel bracelet adds to its luxurious feel, ensuring comfort throughout the day. Whether you're deep-sea diving or just going about your day, you can trust this watch to keep you on schedule. With a diameter of 41.00 mm, it strikes a balance between being prominent on the wrist without feeling bulky.

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Key Features

Longines caliber L667 automatic movement
300m water resistance with sapphire glass protection
Stainless steel case with rotating dive bezel
Black dial with stick and dot indexes
Chronograph function with three sub-dials
42-hour power reserve and 28,800 vibrations per hour
41.00 mm diameter and 21.00 mm lug width

Specifications

Brand

Longines

Family

HydroConquest

Model

Hydroconquest Chronograph Tachymeter Black

Reference

L3.651.4.56.6

Movement

l667

Movement Features

Hours, Minutes, Small Seconds
Date
Chronograph

Case

Stainless Steel 41mm

Dial Color

Black

Crystal

Sapphire

Water Resistance

300

Current Listings

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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Longines hydroconquest 39 mm green

Longines - hydroconquest 39 mm green · $1,995

This Longines HydroConquest is a recent purchase from a US authorized dealer, still in its original packaging and with all papers.

Condition: great condition
Bracelet condition: has a small ding on the clasp
Box and paper status: all included
Additional strap type: aftermarket rubber

Posted at

May 21, 2026, 9:48 AM

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Longines HydroConquest 39mm Blue – Full Set – Excellent Condition

Longines - HydroConquest 39mm Blue · $1,900

This Longines HydroConquest is a 39mm watch with an automatic movement and ceramic bezel, featuring a blue dial and bezel.

Condition: Excellent Condition
Case size: 39mm diameter

Posted at

May 21, 2026, 4:05 AM

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[WTS] RARE CONFIGURATION Longines HydroConquest 42mm | 2026 Gen | Green Ceramic | Green Lacquered Dial | Ref. L3.788.4.06.6 | Never Worn | Full Kit | Warranty Card 5/8/26

RARE CONFIGURATION Longines HydroConquest 42mm | 2026 Gen | Green Ceramic | Green Lacquered Dial | Ref. L3.788.4.06.6 | Never Worn | Full Kit | Warranty Card 5/8/26

Longines - L3.788.4.06.6 · $2,285

This is a rare configuration Longines HydroConquest 42mm watch with a green ceramic bezel and a green lacquered dial. It features an automatic movement, 300m water resistance, and a full kit including the original box, papers, and warranty card.

Condition: never worn
Bracelet: upgraded Longines mesh style bracelet
Movement: Calibre L888.5, automatic, silicon balance spring, 72hr power reserve
Water Resistance: 300m / 30 bar

Posted at

May 20, 2026, 3:53 PM

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