Answer first
IWC does not build a Portofino Automatic with a 46 mm case. Genuine Portofino Automatic models measure 37 mm and 40 mm. The closest 45 mm model in the line is the Portofino Hand-Wound Eight Days, which has a manual movement and a small seconds subdial at 6 o'clock. A listing that says "Portofino Automatic 46" describes a replica with an oversized case, or a listing that mixes two references. Measure the case before you pay.
Genuine Portofino Automatic specs to compare
- Case: 40 mm diameter, 9.2 mm thick, stainless steel or 18k red gold
- Movement: calibre 35111, automatic, 28,800 vph, 42 hours power reserve
- Crystal: convex sapphire with anti-reflective coating on both faces
- Water resistance: 3 bar, which covers splashes only
- Dial: applied indices, leaf hands, date aperture at 3 o'clock
The base for calibre 35111 is the Sellita SW300-1. A genuine watch beats 8 times per second. IWC publishes the diameter in the technical data for each reference, so the number is easy to verify against the caseback.
Common tells on replicas
Case size
Sellers label a watch 46 mm to suggest a larger, heavier feel. Measure across the case at 2 o'clock to 8 o'clock, crown excluded. A true 46 mm listing reads 46.0 mm on calipers. A 40 mm case reads 40.0 mm. If the seller cannot send a photo of the case on a ruler, treat the size as unknown.
Movement
Replicas in this class use a Miyota 9015, a Seagull ST21, or a Chinese copy of the ETA 2824. The Miyota 9015 runs at 28,800 vph and holds 42 hours, so a beat-rate check does not separate it from the Sellita base. Rotor engraving, bridge finish, and the shape of the balance cock do. Ask for the movement name in writing.
Dial, hands, and crystal
Genuine print is sharp under 10x magnification. Replica date fonts sit thin or wide in the window. Genuine sapphire shows almost no scratch after a steel key drags across it. Mineral glass scratches. Replicas use mineral glass in most cases below $150.
Water resistance
Listings quote 30 m or 50 m. Gaskets on replicas are often missing or dry. Do not swim with a replica and do not shower with it. The genuine rating of 3 bar also excludes swimming.
Price and legal status
Replica Portofino listings sell for $60 to $400. US Customs and Border Protection can seize counterfeit watches at import under 19 CFR Part 133. Trademark owners can also file civil claims against sellers. A seized shipment is not refunded by the seller in most cases.
Checks before buying
- Ask for a caseback photo with the reference number readable.
- Ask for the case measured on calipers or a ruler.
- Ask for the movement name and beat rate.
- Ask for the return policy in writing.
- Ask for the weight on a scale. IWC does not publish case weights, so compare two samples of the same listing.
No public record confirms a 46 mm Portofino Automatic reference. Treat the size claim as a seller description, not a factory spec.