Short answer

A fake ref 26470 is almost never a single-tell watch. It fails in layers. The dial squares look flat instead of raised and cut. The bezel screws are decorative rather than functional, with shallow slots and a hard chrome shine. The case edges are soft where a real Royal Oak Offshore has a sharp line between mirror polish and satin brush. And when you turn it over, the movement behind the sapphire back is an Asian chronograph with an AP-shaped rotor, not a Calibre 3126/3840. Any one of those is a red flag. Two or more means walk away.

What the real 26470 is

The 26470 is the 42mm Royal Oak Offshore chronograph that Audemars Piguet introduced in 2014 to replace the 26170. It kept the basic recipe: a 42mm case roughly 14mm thick, the Mega Tapisserie dial, a three-register chronograph layout, and the Calibre 3126/3840 inside. The steel versions moved to black ceramic pusher guards, which is one of the easiest things for a counterfeit to get wrong. Variants run from steel (26470ST) to rose gold (26470OR) and titanium (26470IO), and fakes cluster around the steel Navy and the rose gold models because those are the ones people recognize.

The four checks that matter most

1. The Mega Tapisserie dial

Genuine squares are raised, cut, and sloped, with a fine texture on top. They change tone as you roll the watch in the light, going from deep blue or grey to something brighter at an angle. Fake dials are usually printed or molded shallow. The pattern looks flat, the square edges are fuzzy, and the color barely moves. Look at the subdials too. A 26470 has three, at 12, 6, and 9 (chronograph minutes at 12, hours at 6, running seconds at 9). On a real dial they are cut into the plate with thin, crisp rings. Fakes often get the size wrong or print the rings on top of the surface. The date sits at 3, and the font is light and narrow. A chunky, bold date wheel is a giveaway.

2. Bezel screws and case finishing

Eight hexagonal screws hold the bezel on. On a genuine 26470 they are functional, they thread into the case, and they sit in a properly chamfered recess. White gold has a warm, slightly soft tone. Fake screws are often glued in or purely decorative, with slots cut too shallow and a bright chrome finish. Then run a fingernail along the case edge. Real AP finishing alternates a mirror bevel with an even satin brush, and the line where they meet is sharp enough to catch. On a fake, the brush bleeds over the bevel or the polish was done on a wheel, so the edge feels rounded and the reflections smear.

3. Crown, pushers, and chrono feel

Press the chronograph. A genuine 3126/3840 starts, stops, and resets with a firm, clean click, and the hands snap back to zero every time. A cheap fake feels mushy, and the reset hand often lands slightly off. Pushers on the steel 26470 have black ceramic caps. Fakes use painted plastic or glossy resin that looks wet and reflects light differently from matte ceramic. The crown should screw down smoothly and sit centered, with the AP logo crisp rather than laser-etched into a flat blank.

4. The movement and caseback

The 26470 has a sapphire caseback, so you can check. You are looking for the Calibre 3126/3840: a chronograph built on a Frederic Piguet base, running at 21,600 vibrations per hour, with a rotor that carries the AP crest. Genuine finishing means Geneva stripes, circular graining, polished bevels, and blued or polished screws. Fake movements show stamped plates, unfinished edges, and rotor engraving that looks stamped rather than cut. Read the caseback text as well. The reference and movement numbers are engraved deeply and cleanly, and the font stays consistent across the whole engraving. Fakes have shallow laser text with uneven spacing.

Smaller details worth checking

• Crystal: genuine sapphire has anti-reflective coating on both sides. Fakes often have no coating or a blue-purple tint.
• Strap and clasp: AP rubber has a specific matte finish and a tang or folding clasp with deep engraving. Fake rubber feels slick and smells like a new tire.
• Weight: a steel 26470 on rubber has a heft most fakes miss, though a few cheap ones are heavier because of a brass movement holder.
• Serial match: the case number and movement number should be recorded on the warranty card and match the watch.
• Lume: genuine hands and markers glow evenly and fade slowly. Fakes glow green-blue and die fast.

How to verify before you pay

Ask for photos of the dial straight on, the caseback, both sides of the clasp, and the card. Then take the watch to a watchmaker with a timegrapher and ask them to open it, or bring it to an AP boutique and have them check the serial in the system. A seller who refuses either is telling you something. If the price is far under market for a 26470ST, you are not looking at a bargain.

Where replicas fit

A replica of a 26470 can look right at arm's length and still fail every check above in person. It will not have a 3126/3840, the screws will not be functional, and the finishing will not hold up under a loupe. That is fine if you know what you are buying. It becomes fraud the moment someone sells it as genuine, and that is the situation these checks exist to catch.