Matthew Green was 26 years old when he vanished from his home in Sittingbourne, Kent, after telling his parents he was visiting a friend in London.
After an agonizing six years, Pauline, 63, and Jim, 64, said it felt like "all of their Christmases came at once" when British police delivered the good news.
"We're relieved of course," said Mrs Green.
"The police came on the evening of May 3. Your first thought is one of panic. They said to us 'It's nothing to worry about, Matthew has been found'.
"I've always believed he was alive."
Matthew, now 32, told his family he was visting a friend in Mile End, east London, on April 8 2010.
But that was the last time they ever heard from the roofer, who vanished with his passport, birth certificate, driving licence, bank card, £1,700 in cash and a card which allows him to work on construction sites
His family and friends launched an appeal at the time of Matthew's disappearance - and never gave up hope that they would find him again.
This week he was spotted in Spain by Spanish cops who allegedly became concerned about his welfare.
They carried out DNA tests to prove Matthew was who said he was - but they still can't tell his parents where he is.
In a desperate attempt to get in contact with their son, the Greens have written a letter and sent it to the British Embassy in Madrid.
They now plan to enlist the help of a private investigator to track down their long lost son after Kent Police closed their missing persons enquiry.
Mr Green told the Daily Mail: "After all this time it would be such a relief [to see him] for all of us.
"When we got the knock on the door and she said it's about Matthew but it's nothing to worry about, my heart nearly stopped.
"We didn't know what to say or do."
A Kent Police spokesman said Mr Green had been found in Europe.
He added: "Matthew Green was 26 years old when he was reported missing, and European authorities confirmed in May 2016 that he had been located in Europe.
"His family has been informed and Kent Police has closed its missing person inquiry as of 16 May 2016."