A "fake Portugieser Automatic 31" is a counterfeit copy of an IWC Portugieser sold under a listing name IWC does not use. No official IWC reference is called the Automatic 31. The closest real models are the Portugieser Automatic 40 and the Portugieser Automatic 42, so the number is seller shorthand, not a catalog name.

Two things matter before you spend money. The counterfeit is a generic movement in a lookalike case, and buying or reselling it in the United States is a federal crime. Facts first, then a checklist.

Is there an official IWC Portugieser Automatic 31?

No. IWC publishes its reference numbers, and none of them read "Automatic 31." The Portugieser family uses real references such as 3583 for the Automatic 40 and 5007 for the Automatic 42.

Listing titles on replica sites are built for search engines, not accuracy. The "31" may come from a batch code, a seller's own case measurement, or a garbled echo of older IWC numbers like 5001, 5007, or 3583.

If a seller cannot give a real reference number and a clear photo of the case back, assume the name is invented.

How do you tell a fake Portugieser from a genuine one?

Start at the case back, then work outward. Five checks catch most counterfeits.

• Engraving. Genuine IWC engraving is cut with even depth and sharp edges. Fakes show rounded, filled letters, wrong fonts, and text that does not match the reference.
• Movement. Current Portugieser Automatics have a sapphire display back. Real ones run IWC in-house calibers such as 82200 or 52010 with striped bridges and blued screws. Replicas hide a stock movement under a printed plate.
• Dial. Portugieser numerals are applied metal, thin and sharply finished. Fakes use printed numerals or thick appliqués, and the date window often sits off center.
• Case size and feel. Replicas run thick because a spacer fills the gap between a small movement and a large case. Measure the diameter and thickness against the published figures.
• Papers and price. A matching box, warranty card, and serial number matter. A "new" Portugieser for a few hundred dollars is not real. Genuine ones sell in the thousands, and gold versions cost far more.

What does a replica Portugieser Automatic 31 cost you?

Replica listings often land between $100 and $500. The savings are short lived.

• No service path. IWC service centers refuse counterfeits, and independent watchmakers will not source IWC parts for one. When the movement stops, you replace the watch.
• No resale value. Counterfeits have no collector market, and resale platforms remove the listings.
• Weak materials. Claims of sapphire glass and gold plating often mean mineral glass and thin plating that wears through in months.
• Customs risk. Packages get seized and destroyed, and you receive a letter instead of a watch.

Why is buying one illegal in the United States?

Trafficking in counterfeit goods is a federal crime under 18 U.S.C. § 2320, and the Lanham Act lets trademark owners sue sellers and others in the distribution chain. US Customs and Border Protection can seize and destroy counterfeit watch shipments with no compensation to the buyer. The US Trade Representative keeps watches on its annual review of markets tied to counterfeiting and piracy.

There is no legal way to buy a fake Portugieser Automatic 31 in the US, no matter how a site words the listing.

What should you buy instead?

If the goal is the Portugieser look, several honest routes exist.

• Pre-owned IWC. A used Portugieser costs less than new and comes with papers and a service history.
• Comparable dress watches. Nomos Glashütte Tangente, Junghans Max Bill, and Stowa Marine deliver the same thin, clean dial style.
• Unbranded homages. A watch with no brand name, no logo, and no copied reference number is legal in most markets.
• Budget picks. Seiko Presage, Tissot Le Locle, and Orient Bambino give a formal look for a few hundred dollars.

FAQ

Is a fake Portugieser Automatic 31 waterproof?

Treat any water-resistance claim as unverified. Replicas often skip the gaskets and pressure testing that factory watches get. A splash can fog the dial and rust the movement.

Can IWC service a counterfeit watch?

No. Authorized centers check serial numbers and refuse counterfeits. An independent watchmaker may repair a standard movement inside one, but will not fit IWC parts to it.

Will customs seize a fake watch shipped to the US?

Yes, if inspectors open the parcel. Counterfeit goods are prohibited imports and are destroyed. Sellers who promise guaranteed delivery are often offering a reship, not a legal import.

Do replica Portugieser watches hold value?

No. There is no collector market for counterfeits, and resale apps pull the listings. The money is gone the day the watch arrives.

Bottom line

"Portugieser Automatic 31" is a listing label, not an IWC model. The watch behind it is a counterfeit with a generic movement, no service path, and no resale value, and import or resale in the US carries criminal exposure. If you want the look, buy pre-owned, buy an unbranded homage, or save for the real reference.