Rescue crews who spent 90 minutes searching the sea after a report of a person struggling in the water, found an inflatable doll.
An air and sea search was launched in Newquay, Cornwall, on Monday evening.
An angler had dialled 999 to report a person in the water just north of the harbour.
The doll was recovered from Newquay Bay by the RNLI after it joined a coastguard helicopter in the search.
Gareth Horner, lifeboat operations manager at Newquay RNLI, said the emergency services did not see it as a waste of time and money.
"The 999 caller gave accurate information which led to a successful search and a positive outcome," he said.
"If you think you see somebody in difficulties at sea, do not hesitate, please call 999 and ask for the coastguard."