Newquay Coastguard says hoax phone calls could put lives at risk after a 90-minute search turned out to be a false alarm.
Coastguard volunteers along with Newquay RNLI lifeboats and South West Ambulance Service were called to Crantock beach to reports someone had fallen and was injured.
After an extensive search this was deemed a hoax call.
In a statement on social media, the Coastguard says hoax calls are "a rare occurrence" but stretches ambulance services, "so this person really did put lives at risk".
"When it is reported someone is in distress the unpaid volunteers from the Coastguard and the RNLI drop what they are doing, they leave their full time jobs, they leave their families, they race to offer assistance and aid to those in need.
"We do not do this for any other reason than it is pur calling, it is in our blood.
"So to have our time wasted, to be disrespected in such a way is incredibly annoying, it wastes our time and ties up emergency services that might be needed to save a life elsewhere."