Short answer
A "fake Cartier Santos Large" is a counterfeit copy of the Santos de Cartier in its 39.8 mm case size, the version Cartier sells as the Large model. The genuine watch is steel, automatic, water resistant to 100 m, and runs roughly $7,000 to $8,000 at retail depending on bracelet and year. Copies sell for anywhere from $50 to $600, and the money shows up in four places: the case profile, the dial printing, the bracelet's SmartLink system, and the movement. One more thing before the details. In the US, importing a counterfeit watch is illegal even when it's just for you, and Customs can seize it with no refund and no recourse.
What "Large" actually means in the Santos lineup
Cartier splits the modern Santos de Cartier by case width, and the names are literal. Knowing the numbers matters because sellers use "Large" loosely.
- Large: 39.8 mm wide, about 47.5 mm lug to lug, 9.38 mm thick, Cartier calibre 1847 MC automatic, 100 m water resistance
- Medium: 35.1 mm wide, about 41.9 mm lug to lug, 8.83 mm thick, same movement family
- Santos-Dumont: a different watch entirely, thinner, and quartz on most steel references
Plenty of listings tagged Large measure 40 mm flat and call it close enough. Close enough to what? The whole point of the Santos is the proportions. A millimeter and a half spread across the bezel changes how the curved case sits on the wrist, and it changes how the bracelet drapes.
Where copies give themselves away
Case and crown
The genuine case has a soft curve through the lugs that catches light in one continuous line. Copies tend to look flatter and more machined, because the factory is working from photos, not from a CAD file. Look at the crown too. Cartier sets a faceted blue cabochon into it. Fakes use a plastic bead or a glued piece of glass, and you can usually spot the glue ring under a loupe or a phone macro shot.
Dial
Dial printing is the fastest tell. The genuine Roman numerals are crisp with tight inner corners on the VI and VIII. Fakes blow the paint out slightly and the numerals look bolder than they should. Some Santos references carry Cartier's "secret signature" worked into the VII, so check that area closely on any watch claiming to be current production. Sunburst brushing on the dial should shift smoothly as you rotate it. On copies the brush lines are coarse and the gradient looks striped.
Bracelet
This is the hardest part to fake well. The steel Santos uses SmartLink, which lets you size the bracelet by hand without tools, plus QuickSwitch for swapping straps at the lugs. Pull a link and see whether it releases on its own mechanism or whether you're reaching for a screwdriver. If it needs a screwdriver, it isn't SmartLink. Also flex the bracelet. Genuine links articulate with almost no rattle. Copies feel loose and the end links sit slightly proud of the case.
Movement
Steel Santos de Cartier watches have an exhibition caseback, so the movement is on display. The 1847 MC is an in-house automatic, roughly 40 hours of power reserve, running at 28,800 vibrations per hour. Copies almost never run an in-house caliber. Common substitutes are a Miyota 9015, a Seagull ST2130, or a decorated ETA clone. The rotor engraving may say 1847 MC while the bridges underneath clearly don't match Cartier's finishing. If the caseback is solid steel on a watch that should have a display back, that's your answer.
The legal side in the US
Federal law bars importing merchandise that carries a counterfeit trademark, and that applies to a single watch for personal wear. Customs and Border Protection can seize and destroy the shipment, and the buyer may face civil penalties on top of losing the money. Selling counterfeits is a separate problem, with trademark infringement exposure under the Lanham Act and potential criminal liability for trafficking. Practically speaking, most buyers never get prosecuted. They just lose the watch. There's also no warranty, no service path, and no resale value, which matters if you ever want to move it.
A quick authenticity checklist
- Measure the case. Large should be 39.8 mm wide, not 40 plus.
- Confirm the bracelet releases links without tools.
- Check the crown cabochon for facets and for glue.
- Inspect numeral printing under magnification for bleed and soft corners.
- Confirm a sapphire display back on steel Santos de Cartier references.
- Compare the movement to published 1847 MC photos, not to the rotor text.
- Weigh it. Genuine steel on bracelet lands in a narrow range, and copies usually come in light.
FAQ
Is a fake Santos Large usually quartz or automatic?
Most copies sold as Large are automatic, because that's what buyers expect. The quartz versions usually appear in Santos-Dumont shapes, where the real watch is quartz anyway.
Why do fakes get the case size wrong?
Because they're copying the look from images. The 39.8 mm figure is published, so sellers repeat it, and then ship a case from a shared mold that serves several models.
Can a jeweler tell the difference in person?
Usually within a minute. The bracelet action, the dial print, and the case curve are hard to hide side by side with the real thing.