Now Reading
Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin 41 mm in Titanium

Audemars Piguet Royal Oak Selfwinding Perpetual Calendar Ultra-Thin 41 mm in Titanium


The ultra-thin Royal Oak with perpetual calendar, first appearing in 2018 as a prototype with the name RD#2, continues to evolve. This year, it returns with a new dial design and a new material for the case, bezel and bracelet. To ensure that the watch remains one of the thinnest of its kind, the Le Brassus-based manufacture entrusts the watch with its ultra-thin calibre 5133. The calibre has an overall height of just 2.89 mm.


When the RD#2 was first unveiled in 2018, it was a one-of-a-kind prototype and the world’s thinnest self-winding perpetual calendar watch. In 2019, Audermars Piguet launched the concept watch as a commercial piece under the name Royal Oak Automatic Perpetual Calendar Ultra Flat RD#2. While the 2018 prototype was platinum, an alloy of both titanium and platinum 950 was used in 2019. In the latest interpretation, both the 41 mm case (overall height 6.2 mm) as well as the bezel and bracelet are entirely titanium for the first time. This makes the watch even lighter and ensures better wearer comfort. After all, we’re talking about a watch originally launched as a sports watch – then still made of stainless steel. 

Audemars Piguet polish the screws and chamfers of the bezel and case, as well as the bracelet links. Meanwhile, the other surfaces have a vertical satin-brushed finish. Since titanium is particularly robust, CNC machines prepare the surfaces, while the artisans take care of all the finishing manually. The hour markers and hands are white gold and have a luminous coating. Meanwhile, the sapphire crystal caseback provides a view of the elaborate finishing on the movement. 

New dial design

The predecessor already bid goodbye to the classic Royal Oak tapisserie dial, instead opting for a blue satin-finished dial that changes hue from dark to light blue depending on the incidence of light. With the new Royal Oak Perpetual Calendar Automatic Ultra-thin, the horology house introduces a new type of dial in smoked blue. The sunburst decor ensures that the dial changes from blue to black from the center outwards. For contrast, the calendar indications are black. The month and leap year are at 3 o’clock, the date at 6 o’clock, and the day of the week and day/night indicator at 9 o’clock. The moonphase at the 12 o’clock position remains the same as the previous model.

The ultra-thin calibre 5133

Powering the new Royal Oak Perpetual Calendar Automatic Ultra-thin is the self-winding manufacture calibre 5133 introduced in 2018. This remains the world’s thinnest self-winding perpetual calendar movement at just 2.89 mm in height. The quest for particularly flat watches does not come by chance. Audemars Piguet presented the world’s flattest pocket watch as early as 1921. In 1955, the watch house produced the 5516, the first wristwatch with a perpetual calendar and leap year display. Then, in 1978, the horology house introduced the thinnest automatic wristwatch with a perpetual calendar. The movement had an overall height of just 3.95 mm. 

Audemars Piguet produce each of the 256 components inside the Royal Oak Selfwinding Perpetual Calendar Ultra-Thin to be as delicate as possible, yet as durable as necessary. This is possible thanks to the use of CNC (computer numerical control) and CAD (computer-aided design), which allow particularly precise and space-saving milling. 

To achieve a world record, Audemars Piguet implement two essential, patented designs into the calibre 5133. Firstly, the horology house integrate the cam disc for the end of the month into the date wheel and unite the cam disc for the month with the month wheel. Secondly, instead of extending over three separate levels, the watchmaker positions all functions of the perpetual calendar on a single plane – the result of five years of development work. 

Price & availability

The new Royal Oak Selfwinding Perpetual Calendar Ultra-Thin is limited to 200 pieces and costs 137.000 CHF.

BRAND Audemars Piguet
MODEL Royal Oak Perpetual Calendar Automatic Ultra-thin
REFERENCE 26586TI.OO.1240TI.01
DIMENSIONS Diameter: 41 mm
WATER RESISTANCE 20 m (~2 bar)
DIAL Smoky blue dial with sunburst finish, applied indexes and Royal Oak hands in white gold
MOVEMENT Calibre 5133
FREQUENCY 19,800 vph (2.75 Hz)
FUNCTIONS Perpetual calendar with display of weekday, date, astronomical moon, month, leap year, day and night display, hours and minutes.
PRICE 137.000 CHF