Area Code 0166 – Aosta Valley
The phone area code for Aosta Valley is 0166 (international format +390166). Browse local exchange codes (NXX) and carrier assignments below.
📞 Exchange Codes (NXX) for Area Code 0166
Select a central office code to view local carrier data and detailed information
📍 Geographic Location of Aosta Valley
Geographic Coverage and Administrative Jurisdiction
The Italian area code 0166 is a geographic National Destination Code (NDC) assigned to the Aosta Valley (Valle d'Aosta / Vallée d'Aoste), a special-status autonomous region in northwestern Italy. This code serves the entire administrative territory of the region, including its capital Aosta (Aoste in French) and all surrounding municipalities such as Courmayeur, Saint-Vincent, Châtillon, and Sarre. As a geographic code, 0166 is tied to the PSTN (Public Switched Telephone Network) infrastructure of the region, although VoIP and mobile services may also use numbers with this prefix.
Dialing Formats and Caller Instructions
For local callers within Italy, the number must be dialed in the national format: 0166 XXXXXX (where XXXXXX is the subscriber number, typically 6 digits). The leading '0' is an integral part of the national dialing prefix and must be included when calling from any Italian landline or mobile phone. For international callers, the Italian country code +39 is used, and the leading '0' is dropped: +39 166 XXXXXX. For example, to call a business in Aosta from abroad, you would dial +39 166 123456.
Overlay and Numbering Plan Considerations
Unlike some metropolitan areas in Italy, the Aosta Valley does not currently have an overlay code; 0166 remains the sole geographic code for the region. However, due to number portability, a landline number with the 0166 prefix may be routed to a mobile or VoIP service, and conversely, a mobile number may be ported to a fixed line. Callers should be aware that the prefix does not guarantee a physical location for ported numbers.
Economic and Tourism Context
The Aosta Valley is a major Alpine tourism destination, known for ski resorts such as Cervinia and Courmayeur, as well as the historic sites of Aosta. Consequently, 0166 numbers are used by hotels, mountain refuges, local government offices, and businesses catering to tourists. When calling from abroad, it is advisable to check time zones (CET/CEST) and any applicable international calling rates.