The Secret of Roan Inish (1994)

Set in 1946 Ireland, a young girl named Fiona uncovers the truth about her family's ancestral ties to the selkies, mythical creatures who can transform from seals to humans. With the help of her cousin, Fiona sets out to rescue her long-lost brother who is believed to have been taken by the selkies. Along the way, she learns about the power of family, tradition, and the magic that lies within.