Quick answer
The Royal Oak Offshore reference 25940 is a 42 mm chronograph from Audemars Piguet. It comes from the late 1990s and early 2000s. Fakes of this reference are common. A fake often fails on four points: case thickness, bezel screw shape, dial texture, and movement. The genuine watch runs an automatic chronograph calibre built on a Frederic Piguet 1185 base. Most fakes use a copy of a Valjoux 7750. Bring a loupe, a caliper, and photos of a known genuine example of your exact variant before you buy.
What reference 25940 is
Audemars Piguet launched the Royal Oak Offshore in 1993. The first model was reference 25721ST, a 42 mm steel watch with a case taller than the Royal Oak. Collectors call it "The Beast." Reference 25940 sits in the same 42 mm family.
The family shares one case design: octagonal bezel, eight hex screws, rubber-coated crown, two rubber-coated pushers. Water resistance is 100 m. The dial carries the Mega Tapisserie grid pattern.
One documented 25940 variant is the End of Days, tied to the 1999 film of the same name. Reports put the run at 500 pieces. Treat any other production figure as unverified until you see Audemars Piguet paperwork.
Numbers that matter
- Case size: 42 mm
- Case thickness: about 14 mm on steel examples. Measure the exact watch; variants differ
- Bezel screws: 8 hex head screws
- Dial: Mega Tapisserie grid, raised squares with sharp edges
- Subdials: three, at 9 (running seconds), 12 (30-minute counter), 6 (12-hour counter) on most variants
- Date: window at 3
- Movement: automatic chronograph on a Frederic Piguet 1185 base
- Water resistance: 100 m
Confirm the subdial layout for the exact variant you are looking at. Limited runs use dials that differ from the standard steel model.
Replica tells
Case and thickness
Measure with a caliper. Many fakes run 1 mm to 2 mm thicker than the genuine case, because the donor movement and case kit sit higher. Look at the case flank. The genuine watch has a crisp bevel that runs lug to lug. A fake shows a rounded or uneven edge, and the brushing changes direction near the lugs.
Bezel screws
Count eight. Check slot depth and head shape. On the genuine watch the slot is cut clean, with sharp corners and no burr. Fakes show shallow slots, off-center slots, or screw heads that sit above the bezel plane.
Dial
Use a loupe. The Mega Tapisserie squares sit at one height and share one cut. Fakes show shallow squares, uneven spacing, or printed squares instead of raised squares. Check the date window edges and the printing of the Audemars Piguet name. Letters on a fake are thicker and softer at the corners.
Movement
Ask for a photo of the movement, or have the seller open the case back in front of you. Look at the rotor engraving, the bridge finish, and the balance. Copies use a 7750-type movement. Tells include a rotor that spins with a loud whir, pushers with soft travel, and a chronograph seconds hand that jumps when you press start.
Engraving and papers
Genuine case backs carry the reference number, case number, and serial number. Compare font, spacing, and cut depth to photos of a known real watch. Boxes, booklets, and certificates add value, and they are copied too. A box proves nothing by itself.
Prices
Steel 25940 examples often list in the low-to-mid five figures in USD. Limited editions trade higher, and the End of Days has sold for six figures at auction. Check recent sale results for the exact variant before you set a budget. A price far under market is a signal. Counterfeit watches sell for hundreds of dollars, not thousands. Buying or selling a counterfeit watch is illegal in the United States.
How to verify a 25940 before you buy
- Get photos of the case back, the movement, the dial in raking light, and the case profile from the side.
- Measure thickness and lug width with a caliper.
- Compare bezel screw slots and dial squares to a known genuine example.
- Ask for service history and any Audemars Piguet paperwork.
- Pay for an independent inspection or a service center check before funds move.
- Buy from a seller who offers a return window and a written description of the watch.
Common questions
Is every 25940 a limited edition?
No. Standard steel 25940 models were regular production. Limited runs exist. Check the case back for a number.
Can a local jeweler tell a fake 25940?
Some can. Most cannot open the case or read a movement. Use a watchmaker who services Audemars Piguet, or an authenticator with AP experience.
Does a fake 25940 keep time?
It can. Timekeeping is not proof of authenticity. Case work, dial work, and movement finish separate a real watch from a copy.