The body of Arthur Jones, 73, from Denbigh, was found beneath a tree, six weeks after his disappearance.
He was last seen on 19 June – two days after he arrived on the Greek island. His family flew out to try to find him.
After the inquest, they said they should have been notified sooner that Mr Jones had disappeared.
It was only after he failed to return home to north Wales that Mr Jones’s family realised he was missing.
Outside the hearing, Mr Jones’s son, Jeff, said the alarm could have been raised sooner had they known he was missing.
“We feel let down,” he said.
John Gittins, coroner for North East Wales and Central, praised the family for their efforts to try to locate Mr Jones, a keen and experienced walker.
Two officers from North Wales Police and a mountain rescue expert also flew to the island to join them in their search for the pensioner.
In the end, Mr Jones’s remains were found by a salt farmer on 3 August.
He was identified by dental records. A post-mortem examination could find no conclusive evidence as to the cause of death, the inquest was told.
“He sat down under a tree and at that time he may have succumbed to illness or heat exhaustion from which he did not recover,” said Mr Gittins.