Strap for Portofino Chronograph MecaQuartz Stainless Steel / White / Calf

The IWC Portofino IW3731-07 features a lug width of 18 millimetres. This measurement is the critical parameter for strap compatibility: always measure perpendicular to the case, from the inner edge of one lug to the inner edge of the opposite lug, without confusing this dimension with the case diameter (35 mm). An 18 mm lug width on a 35 mm case preserves the aesthetic balance of the Portofino's classical proportions.

The Portofino IW3731-07, given its essence as a dress watch, pairs superbly with fine leather straps: black or dark-brown alligator for formal occasions, vegetable-tanned calf for daily versatility with natural patina development, or shell cordovan in cognac tones for sophisticated elegance. In sport-elegant contexts, a canvas NATO or rubber strap are valid choices. The 18 mm lug width accommodates any 18 mm strap without compromise.

To change the strap on your IWC Portofino IW3731-07, follow these steps: 1) Position the watch with the lug facing upwards on a soft surface. 2) Using a spring bar tool or fine needle, gently press inward on the spring bar whilst simultaneously releasing the opposite side of the strap. 3) Extract the spring bar and old strap. 4) Insert the spring bar into the new strap, aligning with the IWC lug holes. 5) Press until you hear a click. If you prefer professional assistance, Casati Milano offers personalised strap replacement service.

Absolutely. Any strap compatible with an 18 mm lug width can be mounted on the Portofino IW3731-07 without technical limitations. Artisanal aftermarket straps, crafted from superior leather (alligator, shell cordovan, vegetable-tanned calf), often exceed original equipment quality. MilanoStraps offers online a complete range of 18 mm straps with personalisation: select leather, colour, stitching thread, and anatomical measurements for your wrist. For a bespoke experience, Casati Milano creates made-to-measure straps with direct consultation and 18-month warranty.

Leather strap longevity depends upon material grade, construction quality and usage pattern. A premium-grade leather strap (alligatore, shell cordovan, vegetable-tanned calf) constructed artisanally typically lasts 5–8 years with daily wear, developing a beautiful patina over time. A synthetic rubber strap, being more resistant to wear and temperature fluctuation, can last 10+ years. Straps from Casati Milano include an 18-month warranty and are engineered for decade-long durability. Critical factors: avoid prolonged saltwater immersion (unless specifically treated), protect from excessive humidity and direct heat, periodically apply protective balms to the leather.