Counterfeit watch listings built around the phrase "Swiss made Fifty Fathoms 5050" are not a shortcut to a luxury dive watch. This page does not point you to replica sellers. It answers the question behind the search: how do you separate a genuine Blancpain Fifty Fathoms 5050 from a fake, and what should you verify before money changes hands? Four things decide it. Reference markings that match across watch and paperwork. A movement with the finish Blancpain actually applies. A serial number that ties to the case and the warranty card. A seller who can be held to account. Everything else is guesswork.

What the 5050 reference number tells you

Blancpain organizes the Fifty Fathoms line by reference number, and that reference is engraved on the caseback together with the individual serial. Before you compare dial details, confirm three things agree: the reference engraved on the caseback, the reference on the warranty card or invoice, and the reference shown for that model by Blancpain or an authorized retailer. A mismatch ends the conversation. Counterfeiters work from photographs, so engraved digits often sit off center, carry the wrong font weight, or describe a case material the watch does not have. Ask for a clear, straight-on photograph of the caseback engraving and a separate photograph of the serial. Sellers of genuine watches provide both without argument.

Checks that decide the question

• Case and finishing. Look at how the lugs meet the caseband and how the crown guards are cut. Genuine cases show consistent brushing direction and sharp, even transitions. Fakes show rounded edges and polishing that bleeds across a line it should not cross.
• Bezel action. A dive bezel should index cleanly with a firm, dry click and no lateral play. Loose, gritty, or silent bezels are a common failure point on counterfeits.
• Dial and lume. Check printing under magnification. Genuine text has crisp edges and even spacing. Applied markers sit flush. Lume application is level inside the marker, not pooled or spilling onto the dial.
• Movement finish. Through a display back, look for striped or frosted finishing, chamfered edges on bridges, and engraved markings that follow the plate. Rough, uniform sandblasting with no bevels is a warning sign.
• Paperwork and provenance. Box, warranty card, and service history should tell one consistent story. Serial numbers on card and case should match.
• Price and seller. If a price sits far under current market and the seller cannot produce a serial or a service record, treat the watch as counterfeit until proven otherwise.

Authorized dealer compared with the gray market

Authorized dealer

• Pros: Verified provenance, factory warranty, a service relationship you can use later, and a paper trail that protects resale value.
• Cons: Less negotiating room, waiting lists on popular references, and full retail pricing.
• Best for: Buyers who want certainty and long-term service support.

Reputable gray market or pre-owned specialist

• Pros: Access to discontinued references, sometimes below retail, and faster availability.
• Cons: You carry the authentication burden, factory warranty may not transfer, and condition grading varies between sellers.
• Best for: Buyers who can inspect in person or use an independent watchmaker for a pre-purchase check.

Recommendation

If you want a Fifty Fathoms, buy the real one, from a source that will stand behind it. Have any pre-owned candidate inspected by a watchmaker who handles Blancpain before you pay, and get the authentication in writing. Counterfeits carry no service network, no parts supply, and no resale market, and in many jurisdictions buying one is a legal exposure of its own.