A young man watched the selkies dance; he married one, but she eventually escaped.
An adventurous young man had heard that the seals congregated on an island far out at sea, and held their Halloween in a great cave there. The man sailed to the island, and lay hidden, waiting for the seals. When they arrived, he spotted one exceptionally fine seal. When the seals stripped off their skins, they were clad like men and women. The seal people hid their skins, and the man could hear them dancing and singing in the cave. He took the skin of one exceptionally fine seal girl and hid it beneath the tilfers [floorboards] of his boat. The girl was left behind and the man offered to take her back with him.
Once home, he hid the skin in a corn scroo [stack] and married the girl. They had children and the seal woman's son eventually found out the whereabouts of the skin and told her where it was. She made her children a final splendid feed, took the skin and went to sea. After that when the children were playing by the sea they noticed one seal in particular who was very pretty and tame, and would wave to them.
Brucie Henderson read this in a book of Norwegian stories.