The 30-second commercial featuring residents of Mull, Iona and Tiree will be shown for the first time on 11 May.
The advert's soundtrack is a cover of Supergrass hit Alright by Celtic band Macanta, with some lines of the song sung by the islanders.
CalMac's head of marketing Peter Griffiths said there was "no need to cajole anyone" to take part.
Mr Griffiths said: "They were really excited about it and we got a great response."
The islanders who appear in the advert include Neil Jardine, a fisherman from Iona, and Hannah and Andy Wright and their family from Tiree.
Also featured are Tobermory fish and chip van servers Natalie Livingston and Rebecca Woolcock.
Islanders volunteered to promote their isles in a new TV advert for Caledonian MacBrayne's ferry network.