The cause of Pat Lamb's death has been revealed as "immersion" at an inquest today in Maidstone.
Immersion could mean Mr Lamb drowned, or suffered a cardiac arrest due to shock brought on by entering cold water.
The full details were not given at the short hearing, and the cause of death will be explored in more detail when the inquest resumes in April.
The hearing was told the 28-year-old's identification was confirmed by clothes, plus his phone, wallet and bank cards. A pin in his left arm from a fracture earlier in his life was also examined.
Mr Lamb, from Greenhithe, vanished during a night out with friends on Saturday, December 13 and his body was found in the River Medway at Cuxton Marina nearly a month later.
His disappearance sparked a huge social media to campaign with his family and friends, police, Kent Search and Rescue and members of the public carrying out daily searches to find him.
Images of Mr Lamb on CCTV in Maidstone town centre were published and descriptions of what he was wearing were circulated by his girlfriend and family.
His body was discovered by a teenage girl on Saturday, January 10, and police formally confirmed the identity on Wednesday.
The inquest opened and adjourned at the Archbishop's Palace, in Mill Street, Maidstone, at 10am. It is expected to resume on April 1.