John Tossell, 73, was last seen in Zante, Greece on June 17 after telling his partner Gillian Griffiths he was going to 'stretch his legs'.
He was carrying only a bottle of water and 10 Euros ($16AUD).
The beloved granddad said he was going to walk to a monastery at the top of Mount Skopos and left her by the pool with a book.
They were holidaying Greece after booking a last-minute trip and arriving just three days before.
CCTV shows John heading towards the monastery near the village of Argassi but after that he seemingly vanished.
Gillian, who's now back in their home in Wales, UK, is desperate for answers.
‘It’s like he disappeared off the face of Zante and we have to conclude it could be foul play. ‘We just desperately want John found as soon as possible,' she told Wales Online.
The night before he disappeared Gillian photographed John with a beaming smile on his face and a beer in his hand.
The disappearance is being investigated by police in Greece and the family raised over $12,000 for a search team from Wales to go out there and look for John. But after seven days of searching the team had to stand down.
Gillian is fearful that as the summer season comes to an end and people leave the island, John's disappearance will remain unsolved.
'You can’t just disappear on an island which is 12 miles wide and 25 miles long,' she said.
Anyone with information about John's disappearance can call the local emergency number, which in Greece is 100 or 112, or the British Embassy on 0207 008 1500.