The sea wall between the Gunsite slipway and Le Perquage car park is to be heightened by a foot to give better flood protection to nearby businesses and residents.
In the past few years the area has borne the brunt of winter storms and experts predict the flooding will worsen with climate change.
Work is due to start on 3 July and will take place in staggered 50-metre segments along the 212-metre section of wall.
The Infrastructure Department said a second phase to heighten the wall further eastwards for 118 metres will be undertaken when funding is available, hopefully in 2018.
