A significant amount of terrorist material including explosives, component bomb parts, ammunition and a firearm have been recovered in Co.Antrim.
12 locations have been searched in Larne since the 24th of August as part on a major investigation into dissident republican activity.
It follows the discovery of similar weapons hauls in Carnfunnock Country Park and Capanagh Forest earlier this year.
The joint operation between the PNSI and the Metropolitan Police Service follows the arrest of a Royal Marine from the area who was arrested in Devon last month.
30 year old Ciaran Maxwell faces charges of terrorism, fraud and possession of drugs with intent to supply.
He was remanded in custody after a hearing at Westminster Magistrates court , and is due before the Old Bailey later in the month.
PSNI Assistant Chief Constable Will Kerr thanked the community for their patience.
"This was part of a joint, ongoing, police operation between PSNI and the Metropolitan Police Service in London," he said.
"I am aware of the disruption this has caused to local residents and am extremely grateful for their cooperation and understanding.
"However, as I am sure the people living in Larne will understand, we will take no chances where their safety is concerned and, as a result of the significant terrorist material recovered, I am confident that the area, and Northern Ireland in general, is safer as a result. "