In the island of Saint Helena and the archipelago of Tristan da Cunha, telecommunications are administered by Sure Saint Helena. There is a fixed five-digit number plan, and the country calling code is +290.

Ascension Island is also part of the British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha, but it has a separate calling code and numbering scheme.

From 1 October 2013, all existing 4-digit telephone numbers on St Helena were to be prefixed by a '2' to move from a 4-digit to a 5-digit numbering plan.^[1] The change in numbering resulted from an increased demand for new telephone services and also provided a platform for the future introduction of a cellular network on the island.^[2]

Although Tristan da Cunha shares the +290 code with St Helena, residents have access to the Foreign and Commonwealth Office Telecommunications Network, provided by Global Crossing.^[5] This uses a London 020 numbering range, meaning that numbers are accessed via the UK telephone numbering plan.^[6]

• Telephone numbers in the United Kingdom
• Telephone numbers in Ascension Island