Royal Oak Chronograph

The Audemars Piguet Royal Oak Chronograph adds three registers and a pair of pushers to the Royal Oak’s octagonal bezel, exposed screws, and sharply articulated bracelet. But this is a family with several distinct chapters: compact 39mm originals, later 38mm alternatives, and 41mm models that span two very different movement generations.

Introduced in 1997, the chronograph began with the 39mm 25860, followed by the similarly sized 26300. The 26320 brought the case to 41mm in 2012; the later 26331 is readily distinguished by larger chronograph counters at three and nine and a smaller running-seconds register at six. These generations use the automatic caliber 2385, as do the 38mm 26315 and 26715—smaller cases without abandoning the three-register layout.

The 41mm 26239 introduced the in-house caliber 4401 to the Royal Oak Chronograph in 2021, with the 26240 following in 2022. Here the differences extend beyond the dial: a sapphire caseback reveals the movement, and its flyback mechanism lets the chronograph reset and restart with one press while running. The running seconds also move from six o’clock to three.