A British watersports instructor died while swimming underwater and snorkelling in Greece, it has been reported.
Harry Byatt, 19, was found unconscious on the seabed at a depth of about 30m on 6 August.
A spokesman for the Peligoni Club where the teenager worked on the island of Zakynthos said the alarm was raised five minutes after he went under the water using a mask and monofin.
Mr Byatt was brought back to the surface and given CPR on the rescue boat. Doctors took over when he was on the shore, but were unable to revive him Sky News reports.
"Three doctors, two guests from the UK and one local doctor, and an army medic from the UK, did everything they could to revive him on site whilst awaiting the ambulance," the club spokesman said.
"However, on arrival at the hospital he was pronounced dead. We are working closely with the local authorities in their investigation of the accident. At this time our thoughts and prayers are with his family, friends and colleagues."
Tributes have been paid online to the former Eastbourne College pupil' who is described as a "beloved son, brother, and friend" on social media.
A statement from Eastbourne College said its community was "deeply saddened" by his death.
"Our thoughts are with his family at this incredibly sad time," the statement read. "The college and CCF (Combined Cadet Force) flags will fly at half-mast at the beginning of next term. His parents and sister have asked us to let the college community know and to advise that further details about arrangements will follow in due course."
According to BBC News the Peligoni Club said it was working with local authorities to investigate the incident.
A Foreign Office spokesman said: "We are supporting the family of a British man who died in Zakynthos, Greece and are in contact with the local authorities."