Short answer

A genuine Royal Oak Offshore in titanium uses Grade 5 titanium, a caseback with deep engraving, and an in-house Audemars Piguet caliber. Common fakes use a steel case with a grey coating, a generic chronograph movement, and shallow caseback text. Check four things: weight, caseback engraving, movement finish, and screw heads. No single check proves a watch. Use three or more.

What the real watch is

Audemars Piguet builds the Offshore chronograph in Grade 5 titanium, also written Ti-6Al-4V. Current references include the 26420IO at 43 mm. Earlier 44 mm titanium chronographs carry 26400IO reference numbers. AP lists the 43 mm chronograph at 14.4 mm thick with 100 m water resistance. The movement is caliber 4404: in-house, flyback chronograph, 70-hour power reserve, 4 Hz balance. Older 44 mm models used caliber 3126/3840, a 3120 base with a chronograph module, 60-hour reserve, 3 Hz.

Weight and metal feel

Titanium is about 40 percent lighter than steel at the same volume. A 43 mm titanium Offshore on a rubber strap weighs much less than the steel version of the same size. A titanium watch should feel light in the hand. Steel fakes with a titanium-look coating feel heavy. Grade 5 titanium also reads darker and greyer than steel, and its brushed grain looks softer under light. Hold the watch under a lamp at an angle and compare the tone to a steel bracelet.

Caseback and engraving

Genuine casebacks carry the AP logo, the reference number, the case number, and edition text. The engraving is laser cut with sharp edges and even depth. Fake engraving looks shallow, sandy, or wide. Check the reference number against the model: a 26420IO case should not carry 26400 text. The sapphire caseback ring sits flush on real cases. A raised or rough ring is a warning sign.

Movement checks

Look through the sapphire caseback. Caliber 4404 shows Geneva stripes on the bridges, circular graining on the wheels, polished bevels, and a skeleton rotor with the AP logo in relief. Screw heads are polished and sit in counterbores. Fake movements show stamped decoration, flat bevels, and wrong rotor text. Ask a watchmaker to read the caliber number on the bridge. That number is the fastest hard check.

Bezel screws and case details

Eight hexagonal screws hold the Offshore bezel. The heads sit flush and take a hex key. Screw slot direction changes after service, so alignment alone is not proof. Chronograph pushers on these models are screw-down, and some references use rubber inserts. Check that the threads engage and that the pushers sit in line with the crown. The crown should turn with light drag, not grit.

Dial and hands

The 43 mm Offshore uses a Mega Tapisserie dial with a raised square pattern. Print is crisp at 10x magnification. Date aperture position changes by reference, so confirm it against the reference number before you judge. Hands are faceted and hand-polished. Fake hands show rounded edges and uneven lume fill.

Price, papers, and legal risk

Authorized dealer prices for titanium Offshore chronographs sit near the $30,000 USD mark and up. Secondary prices move with demand. A new titanium Offshore offered far below that level is a fake or a scam. In the US, 18 U.S.C. 2320 makes trafficking in counterfeit goods a federal crime. US Customs and Border Protection seizes counterfeit watches at import. AP service centers refuse to service counterfeit watches, so a fake carries no warranty and no factory repair path.

Limits of photo checks

Photos hide weight, metal tone, and movement finish. Some fakes use real titanium cases with generic movements, so metal alone is not proof. For a high-value deal, have an independent watchmaker open the caseback and verify the caliber and case numbers before payment.