Luna went missing from her home in Oban overnight last Monday into Tuesday, ending up on the Caledonian MacBrayne (Calmac) ferry before being on the MV Isle of Lewis for three return trips.
She was reunited with her owner Sandra Graham on Friday after a Facebook appeal.
It was the first time Luna had been outside with Ms Graham doing everything to attract her home but it is believed that the intrepid feline made her way on to a holidaymaker’s car that boarded the ferry.
Ms Graham told the BBC: “I have had her since she was eight weeks old and she has never been outside before. She is scared of noises and has never tried to get out.
“She sometimes goes off and sleeps around the house so I didn’t think anything of not seeing her on Monday night but then, on Tuesday morning, she didn’t come to my bedroom as usual, when the alarm went off, to get me to feed her and there was no sign of her.
“I went to work and when she wasn’t back on Tuesday night I put it on Facebook. I put her litter tray outside and hung a piece of my clothing out the window for her to get my scent. I went out into the back garden and shook her treats, but there was nothing.
“I just thought, ‘cats will be cats’, there is a lot of greenery around the house and I just thought she would be somewhere close to the house, I never thought she would be in Barra.”
Ms Graham added: “All the ferry crew were really good and the staff in the ferry terminal, they were all brilliant.
“I will let her out if she wants to go but she has made no attempt to get out again.”
Ms Graham’s Facebook appeal was picked up by Calmac staff. They located Luna having caught fleeting glimpses of a cat on the car deck of the ferry as it sailed to Castlebay on Barra.
It is not an unusual sighting for the staff with a number of stray cats roaming the pier at Castlebay.
Luna was kept on board and looked after by Kimmi Graham, a senior catering rating on the MV Isle of Lewis and a volunteer zoo keeper in her spare time, after a member of staff had been in touch from Calmac’s office in Oban having seen the missing cat posters on Facebook.
She said: “There is a little stray black cat in Barra that I always get off and feed and when they said there was a cat on the car deck I thought they were joking and trying to wind me up.
“Everybody came to visit her and she had a wee massage and she had her dinner - I got her some cat food on Barra and some fresh tuna, then we watched TV.
“She was happy enough, she had a look out of the cabin window and I made her a wee bed, but then she slept at the bottom of my bed.”
A similar incident occurred a year ago when a cated boarded a boat from the Western Isles to Oban, travelling around 200 nautical miles.