Wear a smartwatch with your Longines HydroConquest

Wear a smartwatch with your Longines HydroConquest

Smartlet is compatible with the Longines HydroConquest. Lug width: 18mm / 19mm / 21mm / 22mm, supported with watch adapters in the matching width. The watch adapters seat in the lug holes in place of the spring bars. No modification to the watch required. Fully reversible in seconds.
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Longines HydroConquest compatibility

Wear a smartwatch with your Longines HydroConquest

In short Smartlet is compatible with the Longines HydroConquest. Lug width: 18mm / 19mm / 21mm / 22mm, supported with watch adapters in the matching width. The watch adapters seat in the lug holes in place of the spring bars. No modification to the watch required. Fully reversible in seconds.

The HydroConquest is Longines at its most direct. Swiss manufacture movement, 300m water resistance, ceramic bezel, and a price that remains justifiable. The L888 calibre - developed in-house at Saint-Imier - runs at 25,200 vibrations per hour with 64 hours of power reserve. The 41mm in ceramic black or blue bezel has become one of the most recommended entry-level Swiss dive watches on the market. The recommendation holds because the watch delivers. Smartlet completes it.

Wear yours How it works
The problem
Choosing between health data and horological heritage every morning.
The solution
Smartlet One replaces your Longines HydroConquest strap: the watch adapters seat in the lug holes in place of the spring bars, and your smartwatch sits on the same wrist. Both watches run simultaneously, with no modification to the watch and full reversibility in seconds.
Model
Longines HydroConquest
Lug width
19mm / 20mm / 21mm / 22mm / 24mm
References
240covered
Reversible
In seconds

Choose your Smartlet

Compatibility

Longines HydroConquest models supported

Covered references

240 references covered.

ReferenceMaterialDialLugSmartlet
L3.780.4.56.6Steel 39mmBlack19mmCompatible
L3.780.4.96.6Steel 39mmBlue19mmCompatible
L3.742.4.56.6Steel 39mmBlack21mmCompatible
L3.742.4.96.6Steel 39mmBlue21mmCompatible
L3.781.4.56.6Steel 41mmBlack21mmCompatible
L3.781.4.96.6Steel 41mmBlue21mmCompatible
L3.781.3.56.7Yellow Gold 41mmBlack21mmCompatible
L3.781.3.96.7Yellow Gold 41mmBlue21mmCompatible
L3.781.4.06.6Steel 41mmGreen21mmCompatible
L3.781.4.76.6Steel 41mmGrey21mmCompatible
L3.782.4.56.6Steel 43mmBlack21mmCompatible
L3.782.4.96.6Steel 43mmBlue21mmCompatible
L3.781.4.56.9Steel 43mmBlack21mmCompatible
L3.781.4.96.9Steel 43mmBlue21mmCompatible
L3.784.4.56.9Ceramic 43mmBlack21mmCompatible
L3.790.4.06.6Steel 41mmGreen21mmCompatible
L3.790.4.56.6Steel 41mmBlack21mmCompatible
L3.790.4.96.6Steel 41mmBlue21mmCompatible
L3.790.4.96.9Steel 41mmBlue21mmCompatible
L3.782.4.76.6Titanium 43mmGrey21mmCompatible
L3.781.4.99.6Steel 41mmBlue/Red21mmCompatible
L3.788.4.99.6Steel 42mmFrosted Blue21mmCompatible
L3.640.3.56.739mmBlack19mmCompatible
L3.640.3.96.739mmBlue19mmCompatible
L3.640.4.06.639mmBlack19mmCompatible
L3.640.4.56.639mmBlack19mmCompatible
L3.640.4.76.639mmWhite19mmCompatible
L3.640.4.78.639mmWhite19mmCompatible
L3.640.4.79.639mmWhite19mmCompatible
L3.640.4.86.639mmBrown19mmCompatible
L3.640.4.96.639mmBlue19mmCompatible
L3.641.4.56.6Stainless steel 39mmBlack19mmCompatible
L3.641.4.96.6Stainless steel 39mmBlue19mmCompatible
L3.642.3.56.7Stainless steel 41mmBlack21mmCompatible
L3.642.3.96.7Stainless steel 41mmBlue21mmCompatible
L3.642.4.56.6Stainless steel 41mmBlack21mmCompatible
L3.642.4.96.6Stainless steel 41mmBlue21mmCompatible
L3.643.4.56.6Stainless steel 41mmBlack21mmCompatible
L3.643.4.58.6Stainless steel 41mmBlack21mmCompatible
L3.643.4.59.6Stainless steel 41mmBlack21mmCompatible
L3.643.4.96.6Stainless steel 41mmBlue21mmCompatible
L3.644.4.56.6Stainless steel 41mmBlack21mmCompatible
L3.644.4.96.6Stainless steel 41mmBlue21mmCompatible
L3.647.3.16.7Stainless Steel 39mmWhite19mmCompatible
L3.647.3.36.7Stainless Steel 39mmChampagne19mmCompatible
L3.647.3.56.7Stainless Steel 39mmBlack19mmCompatible
L3.647.4.16.6Stainless steel 39mmWhite19mmCompatible
L3.647.4.18.6Stainless steel 39mmWhite19mmCompatible
L3.647.4.56.6Stainless steel 39mmBlack19mmCompatible
L3.647.4.76.6Stainless steel 39mmSilver19mmCompatible
L3.647.4.96.6Stainless steel 39mmBlue19mmCompatible
L3.648.4.16.6Stainless steel 39mmWhite19mmCompatible
L3.648.4.56.6Stainless steel 39mmBlack19mmCompatible
L3.648.4.76.6Stainless steel 39mmSilver19mmCompatible
L3.648.4.96.6Stainless steel 39mmBlue19mmCompatible
L3.649.4.16.6Stainless steel 41mmWhite21mmCompatible
L3.649.4.19.6Stainless steel 41mmWhite21mmCompatible
L3.649.4.56.6Stainless steel 41mmBlack21mmCompatible
L3.649.4.76.6Stainless steel 41mmSilver21mmCompatible
L3.649.4.96.6Stainless steel 41mmBlue21mmCompatible
L3.650.4.16.6Stainless steel 41mmWhite21mmCompatible
L3.650.4.56.6Stainless steel 41mmBlack21mmCompatible
L3.650.4.76.6Stainless steel 41mmGrey21mmCompatible
L3.650.4.96.6Stainless steel 41mmBlue21mmCompatible
L3.651.4.16.6Stainless steel 41mmWhite21mmCompatible
L3.651.4.56.6Stainless steel 41mmBlack21mmCompatible
L3.651.4.76.6Stainless steel 41mmGrey21mmCompatible
L3.651.4.96.6Stainless steel 41mmBlue21mmCompatible
L3.655.4.00.3Stainless steel 39mmWhite19mmCompatible
L3.655.4.56.2Stainless steel 39mmBlack19mmCompatible
L3.655.4.56.6Stainless steel 39mmBlack19mmCompatible
L3.655.4.86.0Stainless steel 39mmWhite19mmCompatible
L3.655.4.86.2Stainless steel 39mmWhite19mmCompatible
L3.655.4.86.3Stainless steel 39mmWhite19mmCompatible
L3.655.4.86.6Stainless steel 39mmWhite19mmCompatible
L3.656.4.56.2Stainless steel 39mmBlack19mmCompatible
L3.656.4.56.6Stainless steel 39mmBlack19mmCompatible
L3.656.4.76.2Stainless steel 39mmWhite19mmCompatible
L3.656.4.76.6Stainless steel 39mmWhite19mmCompatible
L3.656.4.96.2Stainless steel 39mmBlue19mmCompatible
L3.656.4.96.6Stainless steel 39mmBlue19mmCompatible
L3.663.4.76.6Stainless steel 39mmGrey19mmCompatible
L3.664.4.76.6Stainless steel 39mmGrey19mmCompatible
L3.665.4.76.2Stainless steel 47.5mmSilver24mmCompatible
L3.665.4.76.6Stainless steel 47.5mmSilver24mmCompatible
L3.665.8.76.2Rose Gold 18K 47.5mmGrey24mmCompatible
L3.671.4.00.6Stainless steel 41mmGrey21mmCompatible
L3.671.4.76.6Stainless steel 41mmGrey21mmCompatible
L3.672.4.76.6Stainless steel 41mmGrey21mmCompatible
L3.672.4.96.6Stainless steel 41mmGrey21mmCompatible
L3.673.4.76.6Stainless steel 41mmGrey21mmCompatible
L3.673.4.96.6Stainless steel 41mmGrey21mmCompatible
L3.675.4.96.6Stainless steel 39mmBlue19mmCompatible
L3.676.4.56.2Stainless steel 39mmBlack19mmCompatible
L3.676.4.76.2Stainless steel 39mmWhite19mmCompatible
L3.688.4.03.6Stainless steel 39mmBlue19mmCompatible
L3.688.4.19.6Stainless steel 39mmWhite19mmCompatible
L3.688.4.53.2Stainless steel 39mmBlack19mmCompatible
L3.688.4.53.6Stainless steel 39mmBlack19mmCompatible
L3.688.4.59.2Stainless steel 39mmBlack19mmCompatible
L3.688.4.59.6Stainless steel 39mmBlack19mmCompatible
L3.689.4.03.6Stainless steel 41mmBlue21mmCompatible
L3.689.4.53.6Stainless steel 41mmBlack21mmCompatible
L3.689.4.59.6Stainless steel 41mmBlack21mmCompatible
L3.690.4.03.6Stainless steel 41mmBlue21mmCompatible
L3.690.4.19.6Stainless steel 41mmWhite21mmCompatible
L3.690.4.53.2Stainless steel 41mmBlack21mmCompatible
L3.690.4.53.6Stainless steel 41mmBlack21mmCompatible
L3.690.4.58.6Stainless steel 41mmBlack21mmCompatible
L3.690.4.59.2Stainless steel 41mmBlack21mmCompatible
L3.690.4.59.6Stainless steel 41mmBlack21mmCompatible
L3.694.4.03.6Stainless steel 39mmBlue19mmCompatible
L3.694.4.13.6Stainless steel 39mmBeige19mmCompatible
L3.694.4.53.2Stainless steel 39mmBlack19mmCompatible
L3.694.4.53.6Stainless steel 39mmBlack19mmCompatible
L3.694.4.59.2Stainless steel 39mmBlack19mmCompatible
L3.694.4.59.6Stainless steel 39mmBlack19mmCompatible
L3.695.4.03.6Stainless steel 41mmBlue21mmCompatible
L3.695.4.13.6Stainless steel 41mmBeige21mmCompatible
L3.695.4.19.6Stainless steel 41mmBeige21mmCompatible
L3.695.4.53.6Stainless steel 41mmBlack21mmCompatible
L3.695.4.59.6Stainless steel 41mmBlack21mmCompatible
L3.696.4.03.6Stainless steel 41mmBlue21mmCompatible
L3.696.4.13.6Stainless steel 41mmBeige21mmCompatible
L3.696.4.19.6Stainless steel 41mmBeige21mmCompatible
L3.696.4.53.6Stainless steel 41mmBlack21mmCompatible
L3.696.4.59.6Stainless steel 41mmBlack21mmCompatible
L3.730.4.56.6Stainless steel 39mmNegra con efecto "rayos de sol"19mmCompatible
L3.730.4.96.6Stainless steel 39mmBlue19mmCompatible
L3.740.3.56.7Stainless steel with yellow PVD coating 41mmNegra con efecto "rayos de sol"21mmCompatible
L3.740.3.58.7Stainless steel 41mmBlack21mmCompatible
L3.740.3.96.7Stainless steel 41mmBlue21mmCompatible
L3.740.3.98.7Stainless steel 41mmBlue21mmCompatible
L3.740.4.56.6Stainless steel 41mmBlack21mmCompatible
L3.740.4.96.6Stainless steel 41mmBlue21mmCompatible
L3.741.4.56.6Stainless steel 39mmNegra con efecto "rayos de sol"19mmCompatible
L3.741.4.96.6Stainless steel 39mmBlue sunray19mmCompatible
L3.742.2.56.6Stainless steel 41mmBlack21mmCompatible
L3.742.2.58.6Stainless steel 41mmBlack21mmCompatible
L3.742.2.76.6Stainless steel 41mmGrey21mmCompatible
L3.742.3.56.7Stainless steel and yellow PVD coating 41mmSunray black21mmCompatible
L3.742.3.96.7Stainless steel and yellow PVD coating 41mmSunray blue21mmCompatible
L3.742.4.08.6Stainless steel 41mmBlack21mmCompatible
L3.742.4.09.6Stainless steel 41mmBlue21mmCompatible
L3.742.4.98.6Stainless steel 41mmBlue21mmCompatible
L3.743.4.56.2Stainless steel 41mmBlack21mmCompatible
L3.743.4.56.6Stainless steel 41mmBlack21mmCompatible
L3.743.4.96.6Stainless steel 41mmBlue21mmCompatible
L3.744.4.56.6Stainless steel 41mmBlack21mmCompatible
L3.744.4.96.6Stainless steel 41mmBlue21mmCompatible
L3.765.4.56.2Stainless steel 47.5mmBlack24mmCompatible
L3.765.4.56.6Stainless steel 47.5mmBlack24mmCompatible
L3.780.3.78.6Stainless steel and ceramic bezel 39mmSunray grey19mmCompatible
L3.780.3.78.9Stainless steel 39mmGrey19mmCompatible
L3.780.4.56.9Stainless steel 39mmBlack19mmCompatible
L3.780.4.96.9Stainless steel 39mmBlue19mmCompatible
L3.781.3.06.7Stainless steel 41mmGreen21mmCompatible
L3.781.3.06.9Stainless steel 41mmGreen21mmCompatible
L3.781.3.08.7Stainless steel 41mmGreen21mmCompatible
L3.781.3.56.9Stainless steel 41mmBlack21mmCompatible
L3.781.3.58.7Stainless steel 41mmBlack21mmCompatible
L3.781.3.58.9Stainless steel and ceramic bezel 41mmSunray black21mmCompatible
L3.781.3.78.7Stainless steel and ceramic bezel 41mmSunray grey21mmCompatible
L3.781.3.78.9Stainless steel and ceramic bezel 41mmSunray grey21mmCompatible
L3.781.3.96.9Stainless steel 41mmBlue21mmCompatible
L3.781.3.98.7Stainless steel and ceramic bezel 41mmSunray blue21mmCompatible
L3.781.3.98.9Stainless steel and ceramic 41mmBlue sunray21mmCompatible
L3.781.4.05.2Stainless steel 41mmBlack21mmCompatible
L3.781.4.05.6Stainless steel and ceramic bezel 41mmBlack21mmCompatible
L3.781.4.06.9Stainless steel 41mmGreen21mmCompatible
L3.781.4.59.6Stainless steel 41mmBlack21mmCompatible
L3.781.4.76.9Stainless steel 41mmGrey21mmCompatible
L3.781.4.97.6Stainless steel 41mmBlue21mmCompatible
L3.781.4.98.6Stainless steel 41mmBlue21mmCompatible
L3.782.3.06.7Stainless steel 43mmGreen21mmCompatible
L3.782.3.56.7Stainless steel 43mmBlack21mmCompatible
L3.782.3.56.9Stainless steel 43mmBlack21mmCompatible
L3.782.3.58.7Stainless steel 43mmBlack21mmCompatible
L3.782.3.58.9Stainless steel 43mmBlack21mmCompatible
L3.782.3.78.7Stainless steel and ceramic bezel 43mmSunray grey21mmCompatible
L3.782.3.78.9Stainless steel and ceramic bezel 43mmSunray grey21mmCompatible
L3.782.3.96.7Stainless steel and ceramic bezel 43mmSunray blue21mmCompatible
L3.782.3.96.9Stainless steel 43mmBlue21mmCompatible
L3.782.3.98.7Stainless steel 43mmBlue21mmCompatible
L3.782.3.98.9Stainless steel 43mmBlue21mmCompatible
L3.782.4.06.6Stainless steel 43mmGreen21mmCompatible
L3.782.4.56.9Stainless steel and ceramic bezel 43mmSunray black21mmCompatible
L3.782.4.76.9Stainless Steel 43mmGrey21mmCompatible
L3.782.4.96.9Stainless steel and ceramic bezel 43mmSunray blue21mmCompatible
L3.783.4.56.6Stainless steel 41mmBlack21mmCompatible
L3.783.4.56.9Stainless steel 41mmBlack21mmCompatible
L3.783.4.76.6Stainless steel 41mmGrey21mmCompatible
L3.783.4.76.9Stainless steel 41mmGrey21mmCompatible
L3.783.4.96.6Stainless steel 41mmBlue21mmCompatible
L3.783.4.96.9Stainless steel 41mmBlue21mmCompatible
L3.785.4.06.6Stainless Steel 41mmGreen21mmCompatible
L3.788.4.06.6Stainless steel and ceramic bezel 42mmGreen lacquered polished21mmCompatible
L3.788.4.09.9Stainless steel and ceramic bezel 42mmTeal gradient lacquered polished21mmCompatible
L3.788.4.56.6Stainless steel and ceramic bezel 42mmBlack lacquered polished21mmCompatible
L3.788.4.70.6Stainless steel and ceramic bezel 42mmBlack lacquered polished21mmCompatible
L3.788.4.90.6Stainless steel and ceramic bezel 42mmBlack lacquered polished21mmCompatible
L3.788.4.96.6Stainless steel and ceramic bezel 42mmBlue lacquered polished21mmCompatible
L3.788.4.98.6Stainless steel and ceramic bezel 42mmFrosted Blue sunray21mmCompatible
L3.790.4.06.2Stainless steel 41mmGreen21mmCompatible
L3.790.4.09.6Stainless steel 41mmGreen21mmCompatible
L3.790.4.56.9Stainless steel 41mmBlack21mmCompatible
L3.790.4.66.2Stainless steel 41mmBrown21mmCompatible
L3.790.4.66.6Stainless steel and ceramic bezel 41mmSunray brown21mmCompatible
L3.840.4.56.6Stainless steel 44mmNegra con efecto "rayos de sol"22mmCompatible
L3.840.4.96.6Stainless steel 44mmBlue sunray22mmCompatible
L3.841.4.56.6Stainless steel 44mmSunray black22mmCompatible
L3.841.4.96.6Stainless steel 44mmSunray blue22mmCompatible
L3.843.4.56.2Stainless steel 47.5mmBlack24mmCompatible
L3.843.4.56.6Stainless steel 47.5mmBlack24mmCompatible
L3.843.4.96.6Stainless steel 47.5mmBlue24mmCompatible
L3.883.4.56.6Stainless steel 43mmBlack21mmCompatible
L3.883.4.76.6Stainless steel 43mmGrey21mmCompatible
L3.883.4.76.9Stainless steel 43mmGrey21mmCompatible
L3.883.4.96.6Stainless steel 43mmBlue21mmCompatible
L3.890.4.06.6Stainless steel and ceramic bezel 43mmSunray green22mmCompatible
L3.890.4.56.6Stainless steel and ceramic bezel 43mmSunray black22mmCompatible
L3.890.4.56.9Stainless steel and ceramic bezel 43mmSunray black22mmCompatible
L3.890.4.96.6Stainless steel 43mmBlue22mmCompatible
L3.890.4.96.9Stainless steel and ceramic bezel 43mmSunray blue22mmCompatible
L3.769.3.98.7Stainless steel 42mmBlue sandblasted21mmCompatible
L3.779.4.90.6Stainless steel and ceramic bezel 39mmBlack lacquered polished20mmCompatible
L3.779.4.96.6Stainless steel and ceramic bezel 39mmBlue lacquered polished20mmCompatible
L3.769.3.58.7Stainless steel 42mmBlack sandblasted21mmCompatible
L3.779.4.06.6Stainless steel and ceramic bezel 39mmGreen lacquered polished20mmCompatible
L3.769.4.56.6Stainless steel 42mmBlack sandblasted21mmCompatible
L3.769.3.96.7Stainless steel 42mmBlue sandblasted21mmCompatible
L3.769.4.06.6Stainless steel 42mmGreen sandblasted21mmCompatible
L3.769.4.96.6Stainless steel 42mmBlue sandblasted21mmCompatible
L3.769.3.56.7Stainless steel 42mmBlack sandblasted21mmCompatible
L3.779.4.99.6Stainless steel and ceramic bezel 39mmFrosted Blue sunray20mmCompatible
L3.779.4.70.6Stainless steel and ceramic bezel 39mmBlack lacquered polished20mmCompatible
L3.779.4.09.9Stainless steel and ceramic bezel 39mmTeal gradient lacquered polished20mmCompatible
L3.779.4.19.6Stainless steel and ceramic bezel 39mmWhite lacquered polished20mmCompatible
L3.779.4.98.6Stainless steel and ceramic bezel 39mmFrosted Blue sunray20mmCompatible
L3.788.4.19.6Stainless steel and ceramic bezel 42mmWhite lacquered polished21mmCompatible

Longines HydroConquest lug widths: 19mm / 20mm / 21mm / 22mm / 24mm

The HydroConquest is Longines at its most direct. Swiss manufacture movement, 300m water resistance, ceramic bezel, and a price that remains justifiable. The L888 calibre - developed in-house at Saint-Imier - runs at 25,200 vibrations per hour with 64 hours of power reserve. The 41mm in ceramic black or blue bezel has become one of the most recommended entry-level Swiss dive watches on the market. The recommendation holds because the watch delivers. Smartlet completes it. Longines gave the HydroConquest a full next generation overhaul for 2026, with a mesh bracelet option and a frosted blue dial.
Frequently paired

Smartwatches worn with Longines HydroConquest

The most common combinations our customers wear. Find your mechanical watch and discover the right Smartlet edition.

Apple Watch
Series 0 to Ultra 4
Whoop
5.0 / MG
Garmin Forerunner
255 to 965
Samsung Galaxy Watch
Watch 4 to 9 - Classic - FE - Ultra - Ultra2
Withings ScanWatch
Light / 2 / Nova
View all brands
27 brands covered
Also compatible

Other brands

Other iconic models in the Smartlet compatibility library.

Submariner
Daytona
GMT-Master
Datejust
Yacht-Master
Sky-Dweller
Explorer
Seamaster 300m
Speedmaster
Planet Ocean
De Ville
Monaco
Carrera
Formula 1
Aquaracer
Portugieser
Navitimer
Superocean
Avenger
Black Bay
Pelagos
Ranger
Luminor
Submersible
SKX
Prospex
Presage
Khaki Field
Fifty Fathoms
Reverso
SUB 300
Spring Drive
Divers Sixty-Five
Captain Cook
Superman Heritage
El Primero
Monarch
Black Bay 58 GMT
Rolex Datejust 36
Hamilton Jazzmaster
Longines Master Collection
Blancpain Villeret
View all models
Watch brand compatibility guide

Step by step

Replace your strap
01

Replace your strap

The watch adapters seat in your mechanical watch's lug holes in place of the spring bars. Classic, Shadow or Titanium. The spring bar tool is in the box.

Connect your wearable
02

Connect your wearable

Your smartwatch attaches to the central part of the bracelet with its own adapter (Apple Watch, Whoop, Fitbit, Galaxy or Pixel Watch) or a pair of standard watch adapters. Zero modification to the mechanical watch.

Wear both simultaneously
03

Wear both simultaneously

Both watches sit on the same wrist. The smartwatch sits underneath, against the skin; readings taken there are not certified by its manufacturer.

Questions

Frequently asked questions

  • Does Smartlet work with the Longines HydroConquest?
    Yes. The HydroConquest uses 18mm to 22mm lugs depending on case size, supported with watch adapters in the matching width. Watch adapters come in the width chosen at order.
  • Which HydroConquest references are compatible?
    All - 39mm and 41mm at 21mm, 43mm ceramic at 22mm, 36mm at 19mm, and 32mm ladies at 18mm. The full range is within Smartlet's native range.
  • Does Smartlet affect HydroConquest water resistance?
    No. Smartlet uses the spring-bar slots only. The 300m crown seals and case back are not affected.
  • Where can I buy Smartlet for the Longines HydroConquest?
    Smartlet is available at smartlet.io in Classic, Shadow, and Titanium. All finishes are compatible with HydroConquest references from 18mm to 22mm.
  • Does Smartlet damage or modify my mechanical watch?
    No. The watch adapters seat in your watch's lug holes in place of the spring bars. Nothing is modified on the case, lugs or dial, and the change is fully reversible: your mechanical watch can go back on its original strap at any time.