Emergency services rushed to Camber Sands after reports of people getting into difficulty at sea at around 12.40pm.
A 19-year-old man was pulled from the water unconscious by the coastguard before a second man was saved, a South East Coast Ambulance Service (SECAmb) spokeman said.
Both went into cardiac arrest but were resuscitated on the beach before being airlifted to hospital in a ‘life-threatening condition’, according to the SECAmb spokesman.
The coastguard rescue teams from Rye and Dungeness, helicopters from Lydd and Solent, Rye Harbour RNLI lifeboat, beach lifeguards and police searched for a third person, a 19-year-old man from London, last seen in the water.
Hastings and Littlestone RNLI lifeboats and independent inshore boat Pett Level Rescue Boat joined the search.
But the search party was stood down at around 4.20pm.
Some media outlets are reporting the swimmers were attacked by a swarm of jellyfish but police told the Observer this is not true.
The coastguard helicopter landed on the beach and took the teenager to William Harvey Hospital in Ashford after he was resuscitated.
The second man, believed to be in his 30s, was reportedly treated on the beach and taken to the same hospital by the Kent, Surrey and Sussex Air Ambulance.
“A call was received at about 12.30pm to reports of a man who had disappeared while swimming,” a police spokesman said.
“While on the beach, two men were found to have gone into cardiac arrest on the beach having got into difficulty in the sea.
“Both men were given CPR by police officers before ambulance services were on scene.
“Both men were then flown by helicopter to the William Harvey Hospital in Kent where they remain in a serious but stable condition.”
Inspector Mark Evans added: “We are working to establish who these two men are and trace their family and friends.
“We are continuing to support the coastguard and RNLI as they search for the 19-year-old man from London who is still missing.
“It seems this has been three people who have got into trouble while swimming with the changing tides and coastline.”
SECAmb sent two ambulances, two response cars and the Hazardous Area Response Team.
Reports suggest the first helicopter had to refuel but another came to replace it.
Bodybuilder and former glamour model Emma B was on the beach and tweeted: “Praying for the missing person and the two saved today, extremely sad witnessing the CPR.”
Emma also paid tribute to the ‘amazing’ work of the emergency services.
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