UK ham radio call signs

How is a UK ham radio call sign made up?

UK call signs start with G, M or 2, then a digit and a group of letters, like the RSGB’s examples G0ABC and M6XYZ. Intermediate call signs have their own series.

As of October 2026, these are the changes Ofcom brought in during October 2025, as the RSGB summarises them:

• New Intermediate licensees choose an M8 or M9 call sign, not a 2 call.
• Existing Intermediates can amend their call on the Ofcom portal: 2E0ABC becomes M8ABC, and 2E1ABC becomes M9ABC. The locator letter, E here, is required in 2 calls and optional in M8 and M9 calls. It isn’t automatic, and the reservation on your current letters expires after five years.
• Lower-level call signs are revoked automatically when you move up a level.
• You can change your personal call sign once every five years, and you can hold at most five call signs, for example if you look after club calls.
• Special event stations can choose a call sign in a more flexible GB format through the portal. The digit after GB can’t be 3 or 7, which repeaters and beacons use.

The RSGB notes that Ofcom’s portal had launch problems with these changes, so report any trouble changing your call sign to Ofcom directly.

Using your call sign on air

• Keep your station clearly identifiable and give your call sign as often as practicable, in voice or a format that suits the mode.
• Identify again when you change frequency, mode or digital protocol, supervisor, or locator.
• Give your call in full, with the other station’s call first: “Delta Six Eight Charlie from Golf Zero Alpha Bravo Charlie”.
• If someone operates under your supervision, they use your call sign and work to your licence.
• A digital voice radio may store a call sign, so change it if you borrow someone else’s radio.