Short answer

A real Patek Philippe Nautilus 5711/1A measures 40 mm across and 8.3 mm thick. Most fakes measure 9.5 mm to 10.5 mm. The real watch runs caliber 324 S C at 21,600 vibrations per hour. Fakes run a Miyota 9015, an ETA 2824 clone, or a Chinese movement hidden under a decorated bridge plate. Patek Philippe does not sell movements to other makers. No 1:1 copy exists.

Reference facts

  • Reference 5711/1A-010: stainless steel, blue dial, built from 2006 to 2021.
  • Case: 40 mm by 8.3 mm. Water resistance 120 m. Sapphire crystal and sapphire caseback.
  • Movement: caliber 324 S C, automatic, 21,600 vph, 45-hour power reserve, gold rotor.
  • Dial: blue with a horizontal embossed pattern. Applied gold markers. Date at 3 o'clock.
  • Bracelet: integrated steel, brushed and polished links, fold-over clasp with the Calatrava cross.
  • Retail price in 2021: about $34,900. Secondary prices passed $200,000 in early 2022.
  • The line closed in 2021 with the green dial 5711/1A-014, reported at about 1,000 pieces.

Checks that separate real from fake

  1. Measure the thickness with a caliper. 8.3 mm is the number. A reading above 9 mm is not a 5711/1A case.
  2. Open the caseback. The 324 S C shows Geneva stripes, a Gyromax balance, and a gold rotor with the Calatrava cross. Copies show a plated rotor and a bridge that hides a 28,800 vph movement.
  3. Test the beat rate. 21,600 vph is correct. A timegrapher reading of 28,800 vph points to a Miyota or an ETA-based movement.
  4. Read the dial print. "PATEK PHILIPPE" and "GENEVE" stack at 12 o'clock. Stroke width is even and the accent is sharp. Fake prints show thick strokes and a blunt accent.
  5. Inspect the date window at 3 o'clock. The numeral sits centered and the aperture edges are clean. Fakes show an off-center disc and wide gaps.
  6. Check the clasp. Genuine engraving is deep and the Calatrava cross sits flush. Fake clasps show shallow stamping and sharp edges.
  7. Ask for the case number and the movement number. Order a Patek Philippe Extract from the Archives. Patek confirms the reference, both numbers, and the sale date.

Seller claims to treat with caution

  • "Swiss 1:1 clone." Patek Philippe supplies no movements, cases, or bracelets to third parties.
  • "New 5711/1A, full set." The line stopped in 2021. Sealed examples exist, but few.
  • "$6,000, cash." A steel 5711/1A sells for six figures at auction. A four-figure price means a fake.
  • "Papers to follow." The archive extract is the paper that matters.

Before you pay

Buy from a Patek Philippe authorized dealer, or from an auction house such as Christie's, Sotheby's, or Phillips. Ask a watchmaker with Patek parts access to open the case and inspect the movement. Request the Extract from the Archives before you send money. If the seller refuses any of those steps, the watch is not a 5711/1A.