Area Code 23 – Nui

Overview of Tuvalu's +688 23 Geographic Prefix

The international dialing prefix +688 23 is a geographic National Destination Code (NDC) assigned to the island of Nui, one of the nine inhabited atolls of Tuvalu. Tuvalu's national numbering plan, administered by the Ministry of Communications and Transport, follows ITU-T E.164 recommendations. The country code +688 is allocated to Tuvalu, and within this framework, two-digit NDCs (e.g., 20–29) designate specific islands or services. The prefix 23 specifically routes calls to the Nui atoll, located in the central Pacific Ocean.

Geographic Coverage and Administrative Jurisdiction

Nui is a low-lying coral atoll consisting of multiple islets, with the main settlement being Tanrake. It is one of the most remote islands in Tuvalu, and its telecommunications infrastructure is primarily served by fixed-line PSTN connections, with limited mobile coverage. The prefix 23 is used for fixed-line landlines on Nui, and it is not assigned to mobile services. Mobile numbers in Tuvalu typically begin with 7 (e.g., +688 7...).

Dialing Formats and Caller Instructions

To call a fixed-line number on Nui from abroad, dial the international access prefix (e.g., 00 from most countries, or + from mobile phones), followed by Tuvalu's country code 688, then the NDC 23, and the local subscriber number. The local subscriber number length in Tuvalu is typically 5 digits, making the total national significant number (NSN) 7 digits. For example, a local number might be 23 45678, and the full international format would be +688 23 45678.

For callers within Tuvalu, the national dialing format requires dialing the NDC and subscriber number without the country code: 23 45678. However, due to the small size of Tuvalu's telecom network, local calls may also be placed using only the 5-digit subscriber number if the call originates from within the same island or exchange, but this depends on the local network configuration. It is always safer to dial the full national number (23 + 5 digits) to ensure proper routing.

Overlay Considerations and Numbering Plan

Tuvalu does not currently have overlay codes or area code splitting. Each island has a unique two-digit NDC, and there are no plans for overlay as the population and number demand remain low. The numbering plan is closed, meaning that the NDC is always dialed for national calls, even for local calls within the same island, unless the network supports abbreviated dialing.

Caller Instructions for Local and Foreign Callers

For a foreign caller, always use the international format: +688 23 45678. For a local caller within Tuvalu, dial 23 45678. If you are calling from a mobile phone in Tuvalu to a fixed line on Nui, you may need to include the NDC, but some mobile networks may allow direct dialing of the 5-digit number if the call is within the same island. It is recommended to check with your local service provider for specific dialing instructions.

As of 2025, Tuvalu's telecommunications sector is undergoing modernization, with efforts to improve connectivity via satellite and undersea cables. However, the geographic prefix 23 remains a stable identifier for Nui, and no changes to the numbering plan are anticipated in the near future.