Julie LeMilliere vowed never to get another cat when her 17-year-old had to be put down in April.
But she bonded with a stray moggy with a dodgy eye while staying on a Greek island in September.
She and husband Neil feared one-year-old Roo would not last the winter.
So he made a 3,300 mile round trip involving trains, ferries, taxis and a plane to bring him home to London as a 60th birthday present for his wife.
Julie, a PA for a law firm, said: “I was heartbroken when my cat Tis passed away but being with Roo made me realise I could have a pet again.”
Neil, 68, said: “Julie and Roo just bonded and by the end of our break, they were inseparable.
“He was a stray, but used to be looked after by the lady who ran the hotel we stayed in at Batsi.”
The couple, from Haringey, North London, returned to England from Andros on September 24.
They had spent hundreds of pounds with a local vet getting Roo vaccinated, chipped and protected from rabies.
But days before they had to leave, they were told new Brexit rules meant Roo could not travel as hand luggage.
Before Brexit it would have cost them £51 to fly him back but now he had to go in the hold at a cost of more than £1,000.
So the couple left Roo with the hotel owner and hatched a cunning plan.
On October 7, Neil drove to Folkestone, caught the Eurotunnel to Lille in France, where he hopped on a train to Paris.
He then caught a plane to Athens airport, a bus to the ferry port of Rafina, took a 90-minute boat to Andros and a taxi to the resort of Batsi.
Less than 12 hours later, Neil and Roo began the return journey, arriving home at 12.25am on October 10.
The rescue cost the couple over £600 but Neil said: “It is absolutely worth it.”
Julie added: “It’s wonderful and he is now sat on a soft cushion in our kitchen, safe, warm, well-fed and remarkably untraumatised!”