A 'flood warning' from the Environment Agency is in place for the south Cornwall coast, with a lesser 'flood alert' in place for the north coast.
Strong winds, tidal surge and large waves are expected to cause flooding at exposed locations over the high tide on Friday evening.
Locations with damage to defences, buildings and structures, will be especially vulnerable to the predicted large waves.
These locations include: Penzance, Newlyn Green, Marazion, Longrock, Porthleven, St Mawes, Pentewan, Looe, Seaton, Kingsand, Cawsand and Plymouth.
The time of high water on Friday is between 16:41 at Newlyn and 17:49 at Plymouth.
At Plymouth the predicted astronomical tide level is 1.93mAOD. The forecast surge height is up to 850mm, with South South Westerly winds up to Force 9, and wave heights of up to five to seven metres.
Conditions in exposed locations will be dangerous so please remain a safe distance from coastal frontages. Conditions will usually apply two to four hours either side of high tide. We will monitor the situation and update this information if the situation changes.
On the north coast, locations with damage to defences, buildings and structures, will also be vulnerable. These locations include: Bude, Newquay, Perranporth, Portreath and St Ives.
The time of high water on Friday is between 16:41 at Newlyn and 18:03 at Ilfracoombe.