Longines HydroConquest Hydroconquest Automatic 42 Stainless Steel / Black / Mesh
Reference L3.788.4.90.6
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
![[WTS] Longines Hydroconquest Chronograph 41 Ref. L3.783.4 – Travel Box & Manual | $1,850](https://preview.redd.it/tol5a6cznswg1.jpg?width=640&crop=smart&auto=webp&s=7ad74ad9fa0ac8cf212bf09a7327a6f1f42c55d1)
Longines Hydroconquest Chronograph 41 Ref. L3.783.4 – Travel Box & Manual | $1,850
The Longines Hydroconquest Chronograph is a high-performance Swiss diver's watch that features a 41mm case, blue ceramic bezel, and screw-down crown. It houses the calibre L688.2, a column-wheel chronograph movement with a 54-hour power reserve.
- Condition: Very good with minor usage marks
- Case Size: 41 x 51mm stainless steel case with a thickness of 15.6mm and a lug width of 21mm
- Movement: Longines L688.2, automatic column wheel chronograph with 27 jewels, 28,800 bph, and a 54-hour power reserve
- Water Resistance: 300 (30 ATM)
![[WTS] Longines HydroConquest GMT 41mm Black, Full Kit, June 2025](https://preview.redd.it/c4c7iqv7e9wg1.jpg?width=640&crop=smart&auto=webp&s=e250849b5d9c5e65f6e77a3d09a1db59c45552a5)
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
![[WTS] Longines Hydroconquest 39mm Black MINT](https://preview.redd.it/v4pffvhrc5wg1.jpeg?auto=webp&s=814fab44f946ceacdedaffaa381634bee5d33c82)
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
![[WTS] Longines HydroConquest 39mm Green Ceramic Bezel 2026 NEW L3.779.4.06.6 – $2800 + shipping](https://preview.redd.it/aoihsdkp4qvg1.jpg?width=640&crop=smart&auto=webp&s=afddea4ac8c74bd6c345aacb7c77a1c4f9e694fc)
Longines HydroConquest 39mm Green Ceramic Bezel 2026 NEW L3.779.4.06.6 – $2800 + shipping
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
Longines HydroConquest, L3.781.4.06.9, Steel Diver, Olive, Excellent Condition.
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