The lifeboat and coastguard teams were called after an empty kayak was reported in Shoreham yesterday afternoon.
The kayak was located at the east of the harbour arm at around 3.30pm.
A Coastguard spokesman said: “Upon arrival it was established that the occupants had left the kayak and the area as they could not remove it from the shoreline due to it being flooded.
“Due to its position, Shoreham RNLI inshore lifeboat launched to help retrieve it, and then handed it over to Coastguard team.”
The kayak was in poor condition, with no floatation or buoyancy aids or identification marks and was not fit for sea going, the spokesman said.
“Please put contact details on your boards and kayaks if you head to the coast,” said the spokesman.