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Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →IWC’s Portofino range includes several 34 mm and 37 mm watches, not one single new release. The 37 mm Automatic and Moon Phase models were refreshed in autumn 2022; the 34 mm family includes Automatic and Day & Night variants, with a separate Le Petit Prince Day & Night special edition announced in April 2026. Which size is right depends less on diameter alone than on the complication, movement, and exact reference.
What changed, and when?
IWC’s Portofino line dates to 1984, according to the brand. Its 37 mm midsize collection followed in 2014, and IWC says it launched a distinct 34 mm ladies’ collection in 2019. These sizes now span multiple models with different displays and specifications, so “Portofino 34” or “Portofino 37” is not enough to identify a watch.
- 8 September 2022: IWC announced an enhanced 37 mm collection, including Automatic 37 and Automatic Moon Phase 37 models. The brand said they would be available in autumn 2022 through its boutiques, authorized retail partners, and IWC.com. IWC’s 2022 announcement.
- 14 April 2026: IWC announced the Portofino Automatic Day & Night 34 Le Petit Prince, reference IW459806, at Watches and Wonders in Geneva. This is a later, distinct special edition, not part of the 2022 37 mm refresh. IWC’s 2026 announcement.
How do the 34 mm and 37 mm models differ?
The clearest comparison is between specific models. The 34 mm range includes straightforward Automatic models and Day & Night versions; 37 mm options include Automatic models and a Moon Phase complication. The movement and reserve also vary by reference.
| Model or reference | Diameter | Display | Movement and stated reserve | Materials and notable details |
|---|---|---|---|---|
| Automatic 34 variations | 34 mm, as named by IWC | Automatic timekeeping; details vary by variation | Not stated in the cited collection overview | IWC describes six variations with different color combinations, calfskin straps, or five-link stainless-steel bracelets; it says all have a quick-change system. |
| Automatic Day & Night 34, including Le Petit Prince IW459806 | 34 mm | Sun-or-moon day/night display at 6 o’clock | For IW459806: calibre 35180, 50-hour reserve, according to IWC’s 2026 announcement | IW459806 has a stainless-steel case, deep-blue sunray-finished dial, gold-plated hands and appliques, engraved case back, and blue Santoni alligator strap with quick-change system and butterfly clasp. |
| Automatic 37, reference IW658602 | 37 mm | Date | Calibre 32111, 120-hour reserve, according to IWC’s current UK product page | Stainless-steel case, blue calfskin quick-change strap, sapphire display back; 9.4 mm high and rated to 5 bar water resistance, per IWC’s UK listing. |
| Automatic Moon Phase 37 | 37 mm | Moon phase | IWC says the refreshed 37 mm models use its 32000-calibre family and have a five-day reserve; the cited 2022 announcement does not specify a separate reserve for each reference. | IWC describes a solid-gold moon against a blue pad-printed night sky. The brand says the display deviates from the actual lunar orbit by one day after 122 years. |
Specifications in this table are model- or reference-specific, not universal across either size. IWC’s Portofino collection overview describes the broader model families. The IW658602 details are from IWC’s UK product page; regional versions and current availability should be confirmed with IWC.
#1 Best Overall
- Model IW391031
What does the 34 mm Day & Night display do?
On IWC’s Day & Night 34, a disc at 6 o’clock indicates day or night with a sun or moon; tiny stars appear alongside the moon. It is a visual day/night indication, distinct from the moon-phase display on the 37 mm Moon Phase model.
The 2026 Le Petit Prince edition
Reference IW459806 gives the 34 mm Day & Night design a deep-blue, sunray-finished dial, gold-plated hands and appliques, and an engraved case back. IWC specifies automatic calibre 35180 and a 50-hour power reserve, along with a blue Santoni alligator strap and quick-change system. Those details belong to this special edition and should not be assumed for every 34 mm Portofino.
Rank #2
- DURABLE PERFORMANCE – Our most innovative dive-style watch is tested to 100 meters of water resistance and tracks multiple time zones. The Fossil Blue GMT also features a rotating 24-hr bezel, bold oversized crown, and lume indices for easy readability. Made for any adventure. *Not ISO-certified.
- ALL-DAY DURABILITY: 46mm case, 24mm band width, hardened mineral crystal lens resists scratches, GMT movement with GMT analog display echoing craftsmanship of fine watches, men's watch, imported.
- LARGE DIAL STYLE: Round silver and blue stainless steel case with a blue sunray dial and white accents, an ideal analog watch design inspired by classic big face watches.
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- ALL-DAY WATER DEFENSE – Water Resistant up to 100m (330ft): suitable for bathing, swimming or snorkeling, but is not resistant enough to withstand scuba diving; 10 ATM, ideal for those who rotate watches
IWC’s announcement reproduces the line from Antoine de Saint-Exupéry’s The Little Prince: “It is only with the heart that one can see rightly; what is essential is invisible to the eye.”
What distinguishes the 37 mm movement and moon phase?
IWC says its refreshed 37 mm watches use movements from the 32000-calibre family, with a five-day reserve. Its Automatic 37 display back reveals calibre 32111. On the specific IW658602 product page, IWC states a 120-hour reserve for that calibre, along with a date display. These figures describe IWC’s stated specifications, not independent performance tests.
Rank #3
- IWC Portofino Moon Phase Automatic Silver Dial Men's Watch IW459401
The Moon Phase 37 adds a different complication: a display of the lunar phase. IWC says its moon-phase module is integrated into the 32000 movement family and claims the display will deviate from the moon’s actual orbit by one day after 122 years. That precision figure is the manufacturer’s claim in its 2022 announcement, not an independently verified measurement.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Which size should you consider?
Diameter is a useful starting point, but it cannot establish a universal fit winner. IWC describes the 37 mm model as comfortable and says 34 mm models suit slimmer wrists; those are the manufacturer’s descriptions, not independent wrist-fit findings. Compare the exact watch’s case dimensions, strap or bracelet, and complication, then consider how the size looks and feels on your own wrist.
Rank #4
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- Craftsmanship: These straps are typically crafted with meticulous attention to detail. The deployment clasp, usually made of stainless steel 316L, enhances both the functionality and aesthetic appeal of the strap.
- Compatibility: Our Crocodile leather straps with deployment clasps are designed to fit specific For IWC watch models, Likes Portuguese, Portofino and Pilot Mark xvi, and more.. It's essential to verify compatibility with your particular watch model to ensure a perfect fit.
- These materials are chosen for their durability, comfort, and resistance to water, making them suitable for your IWC Schaffhausen Watch.
- Material: Made from high-quality Croro leather and Cowhide leather.
- Consider a 34 mm model if you want the smaller diameter, a choice of strap and bracelet styles in the Automatic variations, or the sun-and-moon display in a Day & Night reference.
- Consider a 37 mm model if you prefer the larger diameter, a date-focused Automatic such as IW658602, or a Moon Phase display.
- Check the reference number before comparing specifications: movement, reserve, case-back design, materials, and water resistance can differ between models at the same diameter.
Are there gem-set Portofino 37 models?
Yes. IWC’s collection overview describes stone-set 37 mm references with 60 diamonds plus 12 stones on the dial, for a stated total of 1.12 carats. The brand describes the diamonds as RJC certified. These figures apply to the stone-set references described by IWC, not to the entire 37 mm family.
Quick Recap
What to verify before buying
- Confirm the full reference and complication; “Portofino 34” or “37” alone does not identify a specification.
- Check the regional product page for the current case, movement, strap or bracelet, water resistance, price, and availability. The IW658602 UK page showed £9,500 including VAT when accessed in 2026; that is a dated regional listing, not a universal or guaranteed current price.
- Try the watch on if fit is important. IWC’s size descriptions are not a substitute for assessing the case on your wrist.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
