A replica Audemars Piguet Royal Oak Perpetual Calendar is a counterfeit-style copy of the ref. 26574 (and its ceramic relatives), sold from about $250 to $1,500. The best versions replicate the 41 mm octagonal case, the Grande Tapisserie dial, and the four-subdial layout. The weakest ones use a flat printed dial, a non-working leap-year window, and a day/night disc posing as a moonphase. Three checks decide quality: case thickness, subdial function, and dial texture.
Why thickness is the first thing to measure
The genuine 26574ST measures 41 mm across and about 9.5 mm thick, which is unusually slim for a perpetual calendar. Most replicas land between 11 mm and 13 mm because a calendar module sits on top of a base movement. Ask the seller for a caliper photo on the caseback edge before you buy. Anything at or under 11 mm usually means a slim base such as a Miyota 9015 with a thin module.
Does the perpetual calendar actually work on a replica?
Rarely in full. The genuine calibre 5134 tracks day, date, month, leap year, moonphase, and week of the year until 2100 without correction. Most replicas deliver day, date, and month through a simple calendar module and stop there, so the watch needs manual correction after February and at every 30-day month end.
- Check whether the leap-year indicator moves at all, since many are static printed discs.
- Watch the date flip on video at midnight; a jumping date with a snap is a good sign.
- Confirm the outer week ring has a real hand, not a fixed pointer glued in place.
How can you tell a real moonphase from a fake one?
A genuine moonphase uses a 59-tooth disc that advances a little each day. Cheap replicas use a 24-hour day/night wheel that shows a sun during daylight hours and fills half the aperture. Track the aperture for 48 hours; slow, steady movement is correct, and a full sweep every 24 hours is not.
Dial and bracelet details that separate tiers
- Grande Tapisserie: the pyramid grid should be raised, sharp, and evenly lit across the dial. Flat or blurry printing signals a low tier.
- Subdial layout: day at 9 o'clock, date at 3, month and leap year at 12, moonphase at 6.
- Logo and hands: an applied metal AP logo, not printed text, plus hands with polished bevels.
- Bracelet: tapered links, brushed tops with polished chamfers, and visible functional screw heads on the sides.
- Caseback: sapphire crystal with engraved text and a rotor finished with Geneva stripes and a skeletonized weight.
Which movements do these replicas use?
Four builds cover most of the market. A Miyota 9015 with a calendar module is reliable and reasonably thin. A Seiko NH35 build is cheaper and thicker. A Chinese clone of an ETA 2824 or 2892 with a module looks closest to the real rotor work but benefits from a service. Top-tier versions use a custom module with a functional leap year, and those are the only ones worth a premium.
What do replica AP Royal Oak Perpetual Calendar watches cost?
- $200 to $400: printed dial, fake moonphase, 12 to 13 mm thick, splash resistant only.
- $450 to $750: textured dial, working day, date, and month, day/night disc, solid bracelet.
- $800 to $1,500: slim case, functional leap year and week hand, decorated movement, sapphire crystal, steel, titanium, or ceramic finishes.
Legal and practical notes in the US
Federal law criminalizes trafficking in counterfeit goods, and US Customs can seize shipments of watches bearing counterfeit trademarks. Personal possession is generally not prosecuted, but resale is a federal offense. Replicas also carry no manufacturer service, so budget for an independent watchmaker if a module jams.
Frequently asked questions
Is a replica Royal Oak Perpetual Calendar waterproof?
Treat it as splash resistant. Gaskets on replica cases are rarely tested, so keep it out of pools, showers, and salt water.
Will the calendar stay correct forever?
No. Even the best replica modules need correction after short months, and only the rare functional clones handle a leap year correctly.
Does the 41 mm size match the genuine watch?
Yes, most replicas copy the 41 mm ref. 26574 case, and a few copy the ceramic 26579CE. Lug width and bracelet taper matter more than the headline number.