The bomb squad will detonate an "unexploded ordnance" in Portsmouth Harbour, found during preparations for the arrival of a new Royal Navy aircraft carrier, police have said.
Hampshire Constabulary said on Wednesday morning that the device was found during a dredging operation.
The detonation comes five days after a wartime device was destroyed by bomb disposal experts at the harbour.
A police spokeswoman said: "Our priority is to keep the public safe and minimise community disruption while the ordnance is detonated by the Royal Navy Explosive Ordnance Disposal."
The Ministry of Defence Police, the Royal Navy, and Portsmouth City Council are also involved in the operation.
A British-made Armstrong Whitworth munition was found at 2am on February 17 in the excavator head of a barge which was dredging Portsmouth Harbour in Hampshire, the Royal Navy has said.
The work is being carried out as part of infrastructure upgrades taking place before the arrival of the Navy's new 65,000-tonne aircraft carrier HMS Queen Elizabeth.
The device was destroyed after divers from the Navy's Southern Diving Unit 2 were lowered to the seabed.