Officials say flooding is likely at Climping seafront and Bracklesham Bay due to unsettled weather.
At Climping beach, waves could overtop the seafront with small amounts of water affecting lands and fields.
Properties near Climping Street car park could be affected.
Conditions are expected to ease on Thursday but could worsen again on Friday.
A spokesman for the UK government said: “Shingle and debris can be thrown by large waves.
“Please avoid walking at the seafront or parking at Climping Street Car Park.”
Gale force eight winds mean tides will be higher at Bracklesham Bay and it will flood Shore Road.
In Bosham High Street, water will be near to or will flood front door steps.
For advice, residents are told to call floodline, which is open 24 hours a day, seven days a week.
The government spokesman added: “ Please call floodline if you need advice on 0345 988 1188.”