Sam Alger, from Norfolk, had been attending Elrow music festival in Viladecans just near El Prat airport in Barcelona on Sunday with his brother and a group of friends.
But he wandered off around midnight and wasn't seen again until his body was discovered on nearby farmland on Tuesday.
The grim discovery was made police and witnessed by friends who had launched their own search of the area as fears mounted over his disappearance.
A Facebook page appealing for help in the search had been set up by his family who then flew out to Barcelona to join the search.
In a post on the Facebook page Find Sam Alger Missing in Barcelona, friends posted: “We are devastated to announce he was dead at the scene.
“No one can quite believe what has happened and everyone is truly heartbroken. Thank you everyone for the help and support and prayers, we appreciate it so much. Sam was one of the kindest most genuine and loving people anyone could wish to know and to have him taken from us is truly heartbreaking.”
The 25-year-old was a performance analyst for the Qatar Stars League professional football team in the Middle East.
The Facebook page revealed that Sam “went missing in Barcelona after riots broke out outside the Elrow club on Sunday the 19th June at around 10pm.
“It is believed he ran into the nearby fields but it is a very rural area and we are not sure if he would have come into contact with any help.”
Los Mossos D'Esquadra, the Catalan police force said initial findings suggested the death was not suspicious.
“We launched a search for him on Monday evening after he was reported missing, asking round hospitals etc,” a spokeswoman from Los Mossos d'Esquadra told The Local.
“His body was discovered the following day in farmland in the Parc Agrari de Viladecans
“There were no signs of violence on the body and everything points to this being a natural death although we are waiting for the results of a post-mortem to determine the circumstances.”
She confirmed that an investigation was ongoing as festival goers complained that the event, which started at 9 am on Sunday and was sold out, had been very badly organized.
"I was also at Elrow and left around 11pm and it was an awful situation! They really should of organised the whole event better! They ran out of water at around 8-9pm and soft drinks shortly after so in my opinion it should have been shut down then," wrote Emma Mason on the Facebook page beneath the post announcing Alger's death.
"The end of this night was the scariest most unorganised thing I have witnessed," wrote Andrea Bainbridge on the Find Sam Alger page.
"I've just returned from Barcelona and was at the same event. It was very, very poorly organised in terms of security and many people were forced to climb fences and run down busy motorways just to try and get taxis," wrote Toby, a commenter on the Mailonline.
"This may be why Sam found himself in unknown areas."
A spokesman at the British Embassy in Madrid told The Local: “We are providing support to the family of a British national who has sadly died in Barcelona”.