Mackenzie Crook as Andy Stone, an agency worker who qualifies as an archaeologist during the series. He is a member of the Danebury Metal Detecting Club (DMDC)'
Toby Jones as Lance Stater, a forklift truck driver for a vegetable wholesaler, an amateur musician and a member of the DMDC
Lucy Benjamin as Maggie, Lance's ex-wife who runs a New Age supplies shop (series 1, 3)
Adam Riches as Tony, Maggie's boyfriend, a pizza restaurant manager (series 1)
Rachael Stirling as Becky, Andy's girlfriend (wife as of series 2), a primary-school teacher
Gerard Horan as Terry Seymour, a retired policeman who is the president of the DMDC
Sophie Thompson as Sheila Seymour, Terry's wife
Pearce Quigley as Russell, a DMDC member
Divian Ladwa as Hugh, a shy and awkward DMDC member
Orion Ben as Varde, a mostly silent DMDC member and girlfriend of Louise. Despite appearing in nearly every episode, and being described by members of the DMDC as very talkative, her only lines of dialogue are in series 2, episode 4, and the 2022 Christmas special.
Laura Checkley as Louise, a forthright DMDC member and girlfriend of Varde
Aimee-Ffion Edwards as Sophie, a university student studying ancient history (series 1, 2)
David Sterne as Larry Bishop, an eccentric farmer and landowner (series 1, 2)
Simon Farnaby as Philip Peters and Paul Casar as Paul Lee, members of "AntiquiSearchers", later "Dirt Sharks", "Terra Firma", and then "Absolut Hunters", a rival group. Lance and Andy call them Simon and Garfunkel because of their passing physical resemblance to the folk rock duo Paul Simon and Art Garfunkel. Both give their full names when questioned by the police in series 2, episode 5 (echoing the rather different vocal pairing of Peters and Lee)