Over 1,000 girls were tested for the role of Fiona, which required the actress to be "Thin, underweight, pale complexion, but perky and not afraid of water."
According to John Sayles in the director's commentary, most of the film was shot in Donegal, Ireland, with some scenes being filmed at the Isle of Mull in Argyll, Scotland.
Although in the original novel the story takes place in Scotland, the filmmakers decided to have the film take place in Ireland for practical reasons.
Roan Inish means " Island of Seals"
Is based on the novel Secret of the Ron Mor Skerry, by Rosalie K. Fry.