A beachgoer discovered a live World War Two grenade in a rockpool.
A man walking along the beach found the grenade at about 15:30 BST on Monday near Westward Ho!, Bideford Coastguard Rescue Team (BCRT) said.
The team was dispatched by Falmouth Coastguard following a call from Devon & Cornwall Police.
The Royal Navy Explosive Ordnance Disposal team from the Devonport naval base in Plymouth was called in while coastguards cordoned off the area, which included part of the South West Coast Path.
The grenade was then safely destroyed on-site in a controlled explosion after being buried and rigged with a small charge.
"A big thank you to the public for their patience and co-operation," BCRT said.
