A pre-owned Longines HydroConquest costs roughly £450–£600 for a quartz model and £850–£1,300 for the ceramic-bezel automatic, as of July 2026 — about half to two-thirds of its near-£1,800 price new. That is the whole appeal of the watch: it is the most affordable serious Swiss dive watch most people can name, and the pre-owned discount makes it more affordable still.
The HydroConquest sits in Longines‘ Conquest sport line and does exactly what a dive watch should: 300 metres of water resistance, a unidirectional rotating bezel, a screw-in crown and a screw-down caseback. The automatic versions run the Longines L888 calibre, an ETA-based movement with a 72-hour power reserve, which is what makes a used one such sensible value against pricier steel divers.
How much does a pre-owned Longines HydroConquest cost in 2026?
These are wider open-market asking prices in GBP, gathered from Chrono24 UK, Goldsmiths and WatchCharts in July 2026 — for guidance, not sold figures, and not Chrono6538’s own prices. Our pieces are checked and guaranteed, so they sit above the bare private-market floor.
| Configuration | Reference family | Pre-owned asking (GBP, Jul 2026) | Notes |
|---|---|---|---|
| Quartz | L3.640 / L3.644 | £450–£800 | The genuine floor; cheaper than any automatic |
| Automatic 41mm, ceramic bezel | L3.781 | £850–£1,300 | The most-traded model |
| Automatic 43mm, ceramic bezel | L3.782 / L3.883 | £950–£1,400 | Larger case; blue dial at the top |
| Rose-gold PVD / two-tone | L3.782.3 | £900–£1,300 | Modest premium, not a big one |
| New 2026 slimmer redesign | L3.779 / L3.788 | Near retail | Too new to have a real used market yet |
Which HydroConquest is the cheapest way in?
Quartz is the floor. A 39mm quartz HydroConquest can be found around £549 on Chrono24 UK, and worn examples dip toward £450. If you want the automatic — and most buyers do — the ceramic-bezel L3.781 in 41mm is the sweet spot: WatchCharts named it the collection’s most-traded model at about £790 market value in July 2026, with clean, boxed examples reaching £1,300. The 43mm L3.782 sits a little higher, and blue dials carry a small premium across the range.
Is a used HydroConquest good value against a new one?
Goldsmiths lists new automatic HydroConquests at roughly £1,700–£1,900 RRP in July 2026. So a pre-owned ceramic-bezel automatic at £850–£1,200 is trading at about half to two-thirds of new, for a watch with the same 300m case, L888 movement and 72-hour reserve. That is the core case for buying this one used: the depreciation has already happened, and what is left is a lot of Swiss dive watch for the money.
What to check before you buy
This is a value line, not a collectible, so condition and completeness matter more than rarity. Look for a crisp ceramic bezel insert (older aluminium-bezel generations are cheaper for a reason), a working screw-in crown, and box and papers where possible. The blue dial is the most-traded configuration if resale ease matters to you. You can see the Longines HydroConquest pieces at Chrono6538 →, each authenticated and guaranteed.
Prices are wider-market asking prices as of July 2026, gathered for guidance only and not offered as Chrono6538’s prices. How a watch has held its value is descriptive, not a forecast — this is not investment advice, and values can fall as well as rise.