Electronic tagging devices are to be fitted to bicycles in a Surrey town free of charge as part of a continuing crackdown on thefts in the borough.
Residents in Guildford, or anyone who cycles into the town to work, will be able to get one of the tags, which will be hidden in the frame of the bike.
Each tag has a unique code number, which will be registered on a database along with the name of the owner.
It is part of an initiative between BBC local radio, police and the council.
Guildford Police, Surrey County Council and BBC Southern Counties Radio are teaming up to run the cycle marking day on 3 May, at the Spectrum Leisure Centre in Guildford.
It will be part of Travel Month, a county-wide initiative focusing on travel and transport throughout May.