Bomb disposal experts were called to Tynemouth beach after a member of the public found a hand grenade.
Police were to the beach near Tynemouth Sailing Club after the rusted hand grenade was found just after 5.50pm on Sunday, March 29.
The device had been found 50m from the sailing club.
A 200m cordon was put in place around the grenade while police evacuated the area and asked members of the public to stay away.
An EOD team from Catterick were called to the scene and carried out a controlled explosion just before 9pm.
A spokesperson for Northumbria Police thanked members of the public for their co-operation.