Jubilee Pool in Penzance, Cornwall, was wrecked in storms that ravaged the south west in January and February 2014.
The pool, which first opened in 1935, is one of a few saltwater tidal open air swimming pools in Europe.
Engineers will repair the original changing rooms and anchor the pool floor to the rock bed.
Martin Nixon, chairman of the Friends of Jubilee Pool group, said he hoped the restoration would create "a sustainable future for this much-loved amenity".
The pool previously closed in 1992 as it had fallen into disrepair, but was restored to reopen in 1995.
The project has been funded by the government's Coastal Communities Fund, Cornwall Council, Cornwall and Isles of Scilly Local Enterprise Partnership, Tempus Leisure, the Friends of Jubilee Pool and Penzance Town Council.
Restoration work on an Art Deco seaside lido badly damaged in winter storms has begun at a cost of £3m.