The coastguard helicopter and inshore lifeboat was called to Bexhill this morning after reports a man had entered the sea.
A spokesman for the HM Coastguard said: "At around 10.00am today (May 20) HM Coastguard received a request for assistance from Sussex police requesting assistance with a search for a possible missing person in Bexhill-on-Sea.
"Bexhill and Eastbourne Coastguard Rescue Teams, RNLI Hastings inshore and all weather lifeboats and HM Coastguard search and rescue helicopter based at Lydd were all sent to assist with a search, alongside Sussex Police.
"After an extensive search of the area, nothing was found and the search was suspended pending further information."
The coastguard and lifeboat teams were searching the water between Galley Hill and the De La Warr Pavilion, according to an eyewitness.
On Twitter, the coastguard said they were assisting Sussex Police in the search for a missing person.
A Sussex Police spokesman said: "Local officers working with HM Coastguard are searching the beach at Bexhill after a report that a man entered the sea there on Monday morning (May 20)."
One eyewitness said teams were searching in lines parallel to the shoreline, 'each search line further out than the last'.
A spokesman for the inshore lifeboat said crews had been called to assist the coastguard but had no further details before they were eventually stood down.
Video by Jim Birrell.