A temporary bridge is being installed while an investigation is underway into damage caused by recent downpours.
Devon County Council is carrying out safety measures at the Alma Bridge on the River Sid, in Sidmouth, East Devon.
Devon County Council is investigating the deterioration of the mudstone rock beneath the western pier of the bridge, after the severe floods in July.
The bridge will be closed tomorrow and Friday to allow the existing ornate bridge parapets to be dismantled for safe keeping and to enable the temporary bridge to be lifted into position. During the closure, the coastal path will also be closed and a temporary diversion will be in place.
It is expected that the bridge will be opened late on Friday or Saturday.
The county council's bridge engineers will be investigating the stability of the existing bridge pier and examining the underlying foundation material in order to check the viability of any underpinning work.