Audemars Piguet Royal Oak Openworked Perpetual Calendar 25829PT
29. January 2020

Audemars Piguet’s Underrated Skeleton Watch

Audemars Piguet (AP) is known within the watch community for its famous master piece, the Royal Oak. The Royal Oak has become a cultural icon thanks to Mr. Gerald Genta, a pioneer and unique designer for high-end luxury sports watches. At almost 50 years old, the Audemars Piguet Royal Oak is a classic piece and is even more popular now that when it was released in 1972.

The openworked pieces such as the double balance-wheeled (ref. 15407) and the recently released Royal Perpetual Calendar Openworked in full ceramic (ref. 26585CE) are especially desired among watch collectors. But there is one other openworked AP that didn’t enjoy as much attention back when it was released. There was no hype, no Instagram, no long waiting lists.

I am talking about the discontinued Royal Oak Openworked Perpetual Calendar reference 25829. The watch was introduced in the late 1990’s and was sold in steel, platinum, yellow gold and rose gold. This master piece is a self-winding perpetual calendar watch indicating the day, date, moon phases, month and leap years.

What’s so special about the openworked watches (most brands call it “Skeleton” watches but not AP) is that they feature a transparent sapphire dial, so you see the movement working. The watch shown in the pictures below is a watch from our friend’s collection (Instagram name: @openworked). As you can see, the watch features the sapphire dial accompanied by white indicators and blackened gold hands. The bracelet and the case are made of 950 platinum.

At 39mm in diameter and only 9.3mm in thickness; this Royal Oak Perpetual Calendar is slightly smaller than the newer generation of Perpetual Calendars which come with a diameter size of 41mm and with a thickness of 9.5 to 9.9mm (depending on the model). The case back is also made of sapphire glass. Both the sapphire display back and the skeletonized dial allow the viewer to see what fine watch-making is all about and clearly define the word “micro-engineering”.

This Openworked Perpetual Calendar is powered by the AP caliber 2120/2802 which consists of 343 parts and has a power reserve of 40 hours. The caliber was originally derived from Jaeger-LeCoultre’s JLC 920 calibre movement and, was back then, the thinnest automatic perpetual calendar movement available on the market.

Hopefully, you are enjoying this piece as much as we do at The Collectors Circle because it’s surely something you don’t see every day.



Audemars Piguet


Royal Oak Openworked Perpetual Calendar Ref. #25829PT


case diameter 39mm, case thickness 9.3mm

When to wear:

Such a stunning piece needs to be treated as such and to be worn on special occasions only. Check out the IG account of @openworked. He knows where and how to wear this master piece.

What we love about the watch:

The Ref. #25829 was a frontrunner for many of AP’s skeleton watches. The movement is complicated indicating the day, date, moon phases, month and leap years, but still fits in the 39mm case.

Images: Instagram @openworked