Longines · HydroConquest

Strap for HydroConquest 43 Automatic Stainless Steel - Pink Gold / Blue / Rubber

Takes 21 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width21 mm
Case diameter43 mm
ReferenceL3.782.3.98.9
FamilyHydroConquest
MovementLongines caliber L888.5 hours, minutes, seconds | date | chronometer
Year2022
CaseCeramic, Stainless Steel

Spring bar

Swiss Standard universal spring bars

The right category for this model · 316L steel, all lug widths 13–26 mm

Straps for the HydroConquest L3.782.3.98.9

Selected for the 21 mm lug width · workshop selection

All 21 mm straps →

The HydroConquest L3.782.3.98.9, seen from the bench

The HydroConquest L3.782.3.98.9 is a professional-grade diving instrument with a 43mm stainless steel case and ceramic bezel. Powered by the COSC-certified L888.5 chronometer movement, it delivers precision within ±4/-6 seconds per day and features hours, minutes, seconds, and date display. Water-resistant to 300 meters, the watch combines Swiss engineering with marine durability through its scratch and corrosion-resistant construction. The 21mm lug width accommodates compatible aftermarket straps, ensuring proper fit and functionality for this technical sports timepiece.

Frequently asked questions

What is the lug width of the Longines HydroConquest L3.782.3.98.9?

The HydroConquest L3.782.3.98.9 requires a strap lug width of 21mm. This measurement must be taken precisely between the inner walls of the case lugs. Incorrect measurement carries compatibility risks: too-narrow lugs damage aesthetics, while oversized lugs create instability. Use a digital calliper positioned perpendicular to the lugs to obtain the exact value.

What strap material is recommended for this dive watch?

The HydroConquest demands materials tolerant of prolonged moisture and marine environments. Vegetable-tanned alligator offers natural patina and tactile distinction; calf leather ensures uniformity and refinement; vulcanised rubber represents the supreme technical choice for frequent diving. We advise against low-grade synthetics, which degrade rapidly in saline conditions.

How do I change the strap on the Longines HydroConquest L3.782.3.98.9?

Strap replacement is performed via the lug spring bars: position the watch horizontally, use a dedicated tool or small lever to gently compress the spring bar, then withdraw the existing strap. Insert the new strap by aligning the lug holes with the pins. Ensure the spring bars sit completely in position. A straightforward operation, executable in seconds with proper tools.

Can I fit aftermarket straps compatible with this Longines?

Yes, any strap with a 21mm lug width is compatible with the HydroConquest L3.782.3.98.9. Aftermarket straps offer greater creative freedom than OEM models: choose between alligator, calf, shell cordovan, vegetable-tanned leather, or textile options. We recommend straps of recognised manufacturing quality, crafted by specialised artisans.

How long does a natural leather strap last on a dive watch?

Longevity depends on usage and tanning method. A vegetable-tanned leather strap, if frequently exposed to marine moisture, may degrade between 12 and 24 months; with chrome tanning, longevity extends to 18–36 months. With proper care—drying after water contact and alternating straps—patina improves without compromising structure. A premium artisanal strap, entrusted to a specialised atelier, includes guarantees that protect this investment.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

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Casati Milano · Via XX Settembre 15, Milan · by appointment only