One of the few independent family-owned watch businesses based in Switzerland’s Le Brassus, Audemars Piguet has always had a soft spot for ultra-thin watches, ever since the company was first established in 1875. The 1972 Royal Oak 5402ST was and still is one very thin watch, with an automatic movement that was thinner than most hand-wound calibres. Now, complications and ultra-thin models: two time-honoured Audemars Piguet specialties come together in the Royal Oak RD#2.
A new record-breaker
1 September 2026
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The Royal Oak RD#2, the world’s thinnest self-winding perpetual calendar at just 6.3 mm thick, marks a new watchmaking record. It has taken five years to develop the new ultra-thin 5133 calibre with perpetual calendar. The challenge was to re-engineer a three-storey movement into a single level, making it ultra-thin while combining and re-arranging functions to boost ergonomy, efficiency and robustness. This patented system features a record-shattering 2.89 mm central rotor. At just 6.30 mm, the redesigned case shaves almost 2 mm off the Royal Oak Extra-Thin Jumbo, making the Royal Oak RD#2 the thinnest self-winding perpetual calendar in the market today. This is the latest chapter in Audemars Piguet’s quest for world firsts which goes back over a century.
Keeping time
Just to offer a little perspective on what this watch means — the Royal Oak Extra-Thin, a 39 mm time-and-date automatic, is significantly thicker, at 8.1 mm. And the Royal Oak Self-Winding, a 41-mm automatic, is 9.8 mm thick.
The platinum case of the RD#2 is water-resistant up to 20 m and RD#2 is engraved on the sapphire caseback. A “Grande Tapisserie” pattern decorates the blue dial featuring blue counters white gold applied hour-markers and Royal Oak hands with luminescent coating. Finally, a strap matching the case gives the watch an additional metallic touch.
