Alex Gibson, 22, was found face down off Blackpool, Lancs.
It was in the evening that the 18-year-old called him last July, saying that she wanted to end her life.
The woman, who has a history of mental health issues, told the Blackpool Inquest she managed to swim to shore.
Alex was found at 5:06 a.m. and died in hospital.
An autopsy showed he had more than double the legal drink-driving limit.
Coroner Alan Wilson said: “Knowing he couldn’t swim, he bravely got into the water and tried to help her.”
EVERY 90 minutes in the UK, a life is lost to suicide. It doesn’t discriminate, touching the lives of people in every corner of society — from the homeless and unemployed, to builders and doctors, to reality stars and footballers. It’s the biggest killer of people under 35, deadlier than cancer and car accidents. And men are three times more likely to commit suicide than women.