Fears a paraglider had crashed into the sea sparked a coastguard alert.
Rescuers said a member of the public thought they saw a paraglider ditch into the water off Osmington.
Coastguard teams from Wyke and Lulworth were alerted, both the inshore and all-weather Weymouth Lifeboats launched and a rescue helicopter was scrambled on Saturday.
Investigations revealed no-one was in danger.
A spokesman for Wyke Coastguard Rescue Team said: "One of our team members who overheard the incident on VHF radio arrived on scene first.
"He located the first informant who pointed out the location of the incident.
"Our team member was then able to liaise with all search assets until a successful outcome was obtained.
"This turned out to be a false alarm with good intent but the first informants did the right thing by dialling 999 and asking for the Coastguard."
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