The construction of the new footbridge, which will replace Alma Bridge, will get under way this month by Mac Plant Construction, which has been appointed by Devon County Council.
The scheme was granted planning permission in November last year.
The new bridge will replace the Alma Bridge, which was designed by architect RW Sampson in the early 1900s.
The new structure will be 40 metres upstream from Alma Bridge.
Relatively short sections of ramp, matching the gradients of the Hanger Path, will connect to the bridge which will provide continued access to the seafront for residents east of the town.
Councillor Stuart Hughes, Devon County Council cabinet member with responsibility for bridges and County Councillor for Sidmouth, said: "It's great news for the town that this scheme will be getting under way at the end of August.
"We have always been committed to providing a new bridge at this end of the town, and while it is slightly further inland, it still ensures that the South West Coast Path, which provides significant economic benefit to the town, will remain close to the seafront.
"Extensive consultation has gone into developing the design of the new bridge which I'm sure will be well used and will be a fitting replacement for Alma Bridge."
A seating and viewing area will be provided on the upper section on the east side.
At the location of the existing Alma Bridge, a seating area and information board will be provided on the west side to commemorate and mark the position of the previous bridges which have been in place for more than 100 years.
The existing structure will be closed for the duration of the work, with a signed inland diversion route.
Emergency access steps from the east beach will be maintained at all times.
The scheme is expected to be completed in Spring 2020, weather permitting. This will ensure the adjacent Ham recreational ground is open and in use for the summer season and Folk Festival.