Longines Hydroconquest L3.784.4.56.9
Ref. L3.784.4.56.9 · Matt black ceramic dial · In production
- Case43 mm
- Thick13 mm
- Lug-to-lug56.1 mm
- Water res.300 m
- MovementAutomatic
- CrystalSapphire
Longines Hydroconquest L3.784.4.56.9 size, specs and price at a glance
The Longines Hydroconquest L3.784.4.56.9 is 43 mm wide and 13 mm thick, with a lug-to-lug length of 56.1 mm. It takes 21 mm straps and ships on a rubber strap. Inside is the L888.5 automatic calibre, water resistant to 300 m. US list price: $4,700 when we last checked longines.com (3 Nov 2026).
Strap shopping? See our Longines lug width chart.
Overview
The Longines L3.784.4.56.9 is a diver watch from the Conquest collection, part of the Hydroconquest family. It has a 43 mm ceramic case, 13 mm thick, 56.1 mm from lug to lug. Longines lists the dial as matt black ceramic. Inside is an automatic movement (calibre L888.5) with 72 h of power reserve. You also get 300 m water resistance, a sapphire crystal and a rubber strap.
Who it suits
- Wrists of roughly 19.0–19.1 cm (7.5–7.5 in), by our Watch Finder sizing guide
- Swimming, snorkelling and diving
Strengths
- Sapphire crystal resists scratches
- 300 m water resistance
- Screw-down crown helps keep water out
- 72 h power reserve survives a weekend off the wrist
Trade-offs
- Long 56.1 mm lug-to-lug can overhang smaller wrists
Written by Watch.co from the published specs below. These are not owner reviews.
Full specifications
Case
| Case diameter | 43 mm | longines.com · 3 Nov 2026 |
|---|---|---|
| Thickness | 13 mm | longines.com · 3 Nov 2026 |
| Lug-to-lug | 56.1 mm | longines.com · 3 Nov 2026 |
| Case material | Ceramic | longines.com · 3 Nov 2026 |
| Crystal | Sapphire | longines.com · 3 Nov 2026 |
| Bezel | Unidirectional rotating | longines.com · 3 Nov 2026 |
| Water resistance | 300 m | longines.com · 3 Nov 2026 |
| Screw-down crown | Yes | longines.com · 3 Nov 2026 |
| Weight | 126.7 g | longines.com · 3 Nov 2026 |
Dial
| Dial colour | Matt black ceramic | longines.com · 3 Nov 2026 |
|---|---|---|
| Date | Date | longines.com · 3 Nov 2026 |
Movement
| Movement type | Automatic | longines.com · 3 Nov 2026 |
|---|---|---|
| Calibre | L888.5 | longines.com · 3 Nov 2026 |
| Power reserve | 72 h | longines.com · 3 Nov 2026 |
Strap / Bracelet
| Bracelet / strap | Rubber strap | longines.com · 3 Nov 2026 |
|---|---|---|
| Lug width | 21 mm | longines.com · 3 Nov 2026 |
Other
| US list price (MSRP) | $4,700 | longines.com · 3 Nov 2026 |
|---|---|---|
| Production status | In production | longines.com · 3 Nov 2026 |
| Style (our classification) | Diver | our classification |
Specs are summarised in our own words from the brand's product page. Each row links its source and the date we checked it. Fields we haven't verified are left out rather than guessed.
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Questions about the Longines Hydroconquest L3.784.4.56.9
How big is the Longines Hydroconquest L3.784.4.56.9?
The case is 43 mm wide, 13 mm thick and 56.1 mm from lug to lug.
What movement does the Longines Hydroconquest L3.784.4.56.9 use?
It uses the L888.5 calibre, a automatic movement with 72 h of power reserve.
Can I swim with the Longines Hydroconquest L3.784.4.56.9?
Yes. It is rated to 300 m.
Does the Longines Hydroconquest L3.784.4.56.9 have a date?
Yes, it shows the date.
How much is the Longines Hydroconquest L3.784.4.56.9?
The US list price was $4,700 on longines.com when we checked on 3 Nov 2026. Prices change, so check before you buy.
Will the Longines Hydroconquest L3.784.4.56.9 fit my wrist?
By our sizing guide it sits best on wrists of about 19.0–19.1 cm (7.5–7.5 in). Use the fit checker on this page to test your own wrist.
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