Announced under a 1 April 2025 embargo, Ulysse Nardin’s Diver [AIR] weighs less than 52 grams with its strap on and less than 46 without. That is a 44 mm watch rated to 200 metres, and the basis of the brand’s claim that it is the lightest mechanical diver yet made.

For scale, against Ulysse Nardin’s own recent divers:

  • Diver 44 (2019): 120.5 g
  • Diver X Skeleton (2021): 105.8 g
  • Diver [AIR] (2025): under 52 g (with strap)
The Diver [AIR] on the orange strap on a wrist, the wearer in a dark jacket, the skeleton dial catching light
Photo · LMC FlowOn the wrist, the orange strap carries most of the colour; the titanium and carbon structure reads dark.

The claimed record is won inside. The UN-374 weighs seven grams, less than a two-euro coin at 8.5. Ulysse Nardin rates the movement for a 5,000 g impact and a 90-hour power reserve.

The bare UN-374 calibre resting on a white cylinder, winding crown still attached
Photo · Ulysse NardinThe UN-374 out of its case. Seven grams, and most of what you are looking at is openings.

Fishing nets and racing-boat carbon

Ulysse Nardin’s parts list reads like a salvage manifest:

  • Case sides (Nylo-Foil): 60 percent recycled fishing net, 40 percent upcycled carbon fibre.
  • Bezel (CarbonFoil): upcycled carbon fibre from IMOCA ocean-racing boats.
  • Bridges, main plate, middle case: 90 percent recycled titanium (TiFast and Thyssenkrupp), some reclaimed from the Swiss biomedical industry.
  • Escapement: upcycled silicon wafers.
Disassembled parts of the Diver [AIR] laid flat: case ring, openworked bridges and the violet silicon escapement
Photo · Ulysse NardinTaken apart, the weight-saving strategy is easier to see: open bridges, a pared-back case ring and little material around the escapement.

The press release frames the list as sustainability. The same materials also serve the engineering brief by taking mass out of both case and calibre.

The bezel gives away its origin too. The upcycled IMOCA carbon finishes in irregular grey patches, closer to marble than to a woven pattern. Our February 2025 hero frame shows the mottling close up.

Open space around the UN-374

Two Diver [AIR] watches: one on the orange strap dial up, one on the white strap turned to show its caseback
Photo · Ulysse NardinBoth straps come in the same box. With the white one turned over, open space becomes as visible as the calibre.

The duo photograph places the orange-strap dial and white-strap caseback side by side. Turned over, the UN-374 appears as an openworked ring of bridges rather than a solid plate.

The same openness carries to the dial-side frame. Under droplets and display light, most of what the crystal contains is empty space.

The Diver [AIR] on its white strap suspended inside a dark display case, droplets on the strap and case
Photo · LMC FlowThe bright white strap sets off a movement pared back to a ring of bridges.

Automatic winding and the dive-watch brief

The release says automatic winding was retained because Ulysse Nardin treats it as essential to the standards a dive watch must meet. A hand-wound movement would have shed more grams. Instead, the barrel was reworked into a flying arrangement to save weight elsewhere.

Ulysse Nardin still rates the result to 200 metres. The release says that at that depth the sapphire crystal would face pressure equivalent to 170 kilograms placed on it.

The Diver [AIR] turned over on its white strap: the UN-374 visible through the open caseback, the reference engraved around the ring
Photo · Ulysse NardinTurned over, the UN-374 is mostly bridges and the spaces between them. The white strap is the second in the box.

Whether the lightness matters underwater is not something the release claims, and not something we have tested. The saving against the brand’s own Diver 44 is 68.6 grams by the release’s arithmetic.

Price and availability

Production. Neither the release nor the current official exact-reference pages state a production status or an edition size.

Retail. €34,700 / $34,300 / CHF 32,500, as of Apr 2025 (launch prices; CHF/EUR/GBP incl. VAT, USD excl., as the release states them)

Specification

Case

Diameter
44 mm
Height
14.7 mm (release)
Materials
recycled titanium middle case, Nylo-Foil side parts, CarbonFoil bezel
Crystal
domed sapphire
Water Resistance
200 m

Movement

Calibre
UN-374
Type
skeleton automatic, in-house
Functions
hours, minutes, seconds
Winding
self-winding
Barrel
flying (open) barrel
Power Reserve
90 hours
Frequency
3 Hz (21,600 vph)
Components
199 parts / 21 jewels
Materials
silicon balance & escapement; 90% recycled titanium bridges & main plate

Weight

Total
under 52 g (with strap)
Head
under 46 g
Movement
7 g

Details

Dial
minimal skeleton, black indexes & hands, white Super-LumiNova
Impact
5,000 g (movement impact resistance of the UN-374, per the release; the current official page broadens the figure to the watch)
Straps
two interchangeable elastic fabric (orange, white), tool-less, R-STRAP compatible

Price

Retail
€34,700 / $34,300 / CHF 32,500, as of Apr 2025 (launch prices; CHF/EUR/GBP incl. VAT, USD excl., as the release states them)

Sources

About this article

Written from Ulysse Nardin's press material for the Diver [AIR]. The Crown Journal did not independently test this watch; all figures are the manufacturer's. The photographs credited to LMC Flow are ours, dated February and April 2025 by their camera metadata; they show the watch, not measurements, and establish no first-hand testing.

Accountable editor
Jimmy Jonevret
Published
Updated
Photography
LMC Flow · Ulysse Nardin

This article has been corrected. See corrections.

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