Consultant orthopaedic surgeon Stuart Calder, 52, from Leeds, drowned along with a 44-year-old man and a 42-year-old woman from St Austell in the incident off Mawgan Porth beach in Newquay on Sunday afternoon.
They had been pulled from the sea after getting caught in a “rip current” but were confirmed dead in hospital.
Four teenage boys – two aged 18, one aged 16 and one aged 15 – were also taken to hospital but were not seriously injured.
The RNLI said yesterday that one of the victims may have been trying to help a stricken surfer.
Gareth Horner, lifeboat operations manager, said: “Mawgan Porth is a dangerous beach. We don’t know the exact circumstances or the ability of the people that were rescued.
“My understanding is that they were in two groups and that one of the casualties actually entered the sea to assist other people who were in trouble.”
The emergency services received several 999 calls from onlookers describing how seven people had been caught in a rip current at about 1.20pm.
Cornwall air ambulance, North Devon air ambulance and a search and rescue helicopter were all dispatched along with ground paramedics, police and Coastguard officers.
Mr Horner described conditions at the beach at the time as “not really very good for surfing and bodyboarding”.
Two RNLI volunteer crews were landed ashore to help paramedics deliver CPR to two of the adults.
The casualties were flown to Royal Cornwall Hospital in Treliske, where they were confirmed dead on arrival.
A third man was spotted by the Royal Navy helicopter inside the surf line and was winched onto the beach, where CPR was carried out. He was later confirmed dead on arrival at hospital.
Formal identification of the victims was expected today.
Inspector Dave Meredith, of Devon and Cornwall Police, said he could “not comment either way” on whether the surfers were related. He described the rescue operation as “prompt and professional”.
Lifeguards were not patrolling the area, as they only do so between March and September.
However, a spokeswoman for the RNLI said lifeboats “on call 24/7” could launch within 10 minutes all year round.
She confirmed a review of the beach’s lifeguard cover during the autumn and winter holidays would be undertaken.
Stephen Gilbert, MP for St Austell and Newquay, said it was now important to see if “lessons can be learnt” to prevent a further such tragedy.
“My deepest sympathies go out to the families and friends of those who tragically lost their lives over the weekend,” the Liberal Democrat MP said.
“While our coastline provides some of the most beautiful scenery and unrivalled opportunities for surfing, it can also be a very dangerous place.
“It’s important for the police and emergency services to see what lessons can be learned from this incident and if anything can be done to prevent the same thing happening to someone else.”