Audemars Piguet Unveils the Royal Oak Selfwinding Perpetual Calendar Openworked with the All-New Calibre 7139

Source: Audemars Piguet

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Audemars Piguet has pulled back the curtain on the Royal Oak Selfwinding Perpetual Calendar Openworked, now powered by the brand-new Calibre 7139. Housed in a 41mm case that pairs titanium with Bulk Metallic Glass, this is more than an iterative update. It represents a meaningful shift in how AP approaches the perpetual calendar complication, pairing next-generation movement architecture with the kind of openworked artistry that has defined the Royal Oak Perpetual Calendar for decades.

The reference 26685XT.OO.1320XT.01 replaces last year's 150th Anniversary limited edition — a watch that served as the final curtain call for the outgoing Calibre 5135. Where that piece looked backward with reverence, this new Royal Oak looks forward.

A perpetual calendar is one of watchmaking's most intellectually impressive complications. It tracks the date, day, month, and leap year automatically — accounting for the varying lengths of months without needing manual correction until the year 2100. It's essentially a miniature mechanical computer on the wrist, built on layers of cams and gears that quietly "know" what the calendar is doing at all times. Now imagine stripping away the dial and letting someone watch all of that happen in real time. That's what makes an openworked perpetual calendar so extraordinary — and so difficult to execute well.

The Movement That Changes Everything

Calibre 7139 is the openworked evolution of the Calibre 7138, which debuted in 2025 as part of AP's 150th anniversary celebrations. The headline innovation carries over: the patented "all-in-one" crown correction system. Traditional perpetual calendars have long required recessed corrector pushers and specialized tools to adjust their displays — a process that made even seasoned collectors nervous. Calibre 7139 eliminates that entirely. Through four crown positions, the wearer can wind the movement, set the time, and adjust every calendar function without ever reaching for an external tool.

The system also allows bidirectional correction. If you overshoot a date, you can simply reverse it — a practical detail that removes one of the last remaining friction points of living with a perpetual calendar. The movement comprises 423 components, beats at 28,800 vibrations per hour, and delivers a ~55-hour power reserve. Compared to the outgoing Calibre 5135's ~40-hour reserve and 19,800 vph frequency, the generational leap is substantial.

The Calibre 7139 through the sapphire caseback — pink gold openworked rotor and bridges, with "Titane" and "Pd500" engravings confirming the case materials. Source: Audemars Piguet.

AP's complications and R&D teams worked closely with the manufacture's traditional finishing atelier to ensure the skeletonized bridges frame the calendar displays rather than compete with them. The result is a movement that rewards extended viewing — you can trace the gear trains and lever systems responsible for tracking months, leap years, and moon phases — while remaining easy to read at a glance.

Titanium Meets Bulk Metallic Glass

The 41mm case measures 9.5mm thick — slightly thinner than the 9.9mm profile of its predecessor — and combines two materials that have become central to AP's design vocabulary. The case middle and crown are crafted from lightweight titanium with a satin-brushed finish, while the bezel, caseback frame, and bracelet studs are fashioned from Bulk Metallic Glass, or BMG.

The contrast between satin-brushed titanium and mirror-polished BMG is visible at every hexagonal screw. Source: Audemars Piguet.

BMG is a palladium-based metallic alloy (approximately 50% palladium) with an amorphous atomic structure — meaning its atoms are arranged like glass rather than in the ordered crystalline pattern of conventional metals. First developed in the 1960s, it has since found applications ranging from microelectronics to aerospace. In watchmaking, that amorphous structure produces a distinctive mirror-like polish and exceptional scratch resistance. Against the matte grain of the titanium surfaces, the BMG components create a visual interplay of reflective and subdued textures that emphasizes the Royal Oak's sculptural geometry.

Water resistance has been improved to 50 meters, a meaningful upgrade from the 20-meter rating that was standard across previous Royal Oak perpetual calendars. Eliminating the recessed corrector pushers (thanks to the crown-based adjustment system) made this improvement possible.

This pairing reinforces the idea that the watch is less about precious metal status and more about technical sophistication — an approach that resonates with collectors who want something rare, but not in the traditional gold-or-platinum sense. If you know what BMG is and why it's difficult to work with, you already understand the message.

The integrated bracelet alternates satin-brushed titanium links with mirror-polished BMG studs. Source: Audemars Piguet.

A Dial You Can't Stop Looking Into

Skeletonization at this level isn't simply about removing material for visual drama. It's about revealing architecture and hand-finishing that would normally be hidden beneath a solid dial — bridges, bevels, and internal angles that represent hundreds of hours of work by AP's traditional atelier. The challenge is that openworked perpetual calendars can easily sacrifice clarity for spectacle. What AP has achieved with the Calibre 7139 is a movement where the decoration and the information share the same visual space without competing.

Through the sapphire dial: pink gold markers and hands frame the openworked Calibre 7139, with smoked subdials maintaining legibility. Source: Audemars Piguet.

The sapphire dial serves as a transparent window into the Calibre 7139, and AP has rethought the display layout for improved readability. The perpetual calendar indications follow a European format: the day of the week sits at 9 o'clock, the date at 12, the month and leap year at 3, and an astronomical moon phase with a black aventurine disc at 6. The subdials feature lightly smoked, see-through centers ringed by smoked external zones, maintaining legibility while preserving the openworked drama beneath. An inclined inner flange carries the week number markings, with the scale beginning at "1" at the 12 o'clock position — a subtle but practical refinement.

The astronomical moon phase at 6 o'clock features a photorealistic moon against a black aventurine disc, framed in pink gold. Source: Audemars Piguet.

Pink gold applied hour markers and Royal Oak hands with luminescent coating provide warm contrast against the grey tones of the movement's rhodium-finished bridges. The choice of pink gold carries through to the movement side, where the openworked rotor, barrel bridge, and balance wheel bridge share the same warm tonality. The watch reads as a cohesive object whether viewed from the front or through the sapphire caseback.

A Legacy of Perpetual Innovation

The perpetual calendar holds a special place in Audemars Piguet's history. The manufacture produced the world's first perpetual calendar wristwatch with a leap-year indication in 1955 (ref. 5516), and the complication became a cornerstone of the Royal Oak collection in the 1980s. For decades, AP relied on movements derived from the ultra-thin Calibre 2120, itself descended from the Jaeger-LeCoultre Calibre 920 of the late 1960s. That lineage evolved through the Calibre 5134 and its openworked sibling, the 5135, before reaching its conclusion with last year's 150th Anniversary edition.

Calibre 7139 represents the decisive break. Built entirely in-house, it is not an evolution of the old architecture but a ground-up reimagining of what a perpetual calendar movement should be today. The emphasis on crown-based correction, bidirectional adjustment, and improved power delivery reflects a manufacture thinking seriously about how collectors actually live with their watches — not just how they admire them.

Key Specifications

The Bottom Line

With the Royal Oak Selfwinding Perpetual Calendar Openworked, Audemars Piguet has made one of haute horlogerie's most complex complications feel genuinely approachable without sacrificing visual spectacle. The Calibre 7139 is a signal from Le Brassus that tradition and user-focused innovation are no longer in tension, but working in concert. For collectors who have long admired the Royal Oak Perpetual Calendar from a distance, this may be the generation that closes that gap.