One of Njord’s main myths–you could argue that it is the most important of His myths–describes how he married Skadi, the daughter of an ice jotun. The myth follows the myth of “The Theft of Idunna’s Apples” in the Skáldskaparmál from Snorri’s Prose Edda.
First, a summary of the theft of Idunn’s Apples:
Odin, Loki and Hœnir were out journeying. Hungry, they came across a herd of oxen, killed one, and started cooking it. However, it refused to cook. The jotun Thjazi, disguised as an eagle, offered to help make the fire cook properly if they left him have some of the ox as well. They agreed. The food was finally cooked and Thjazi flew down and started devouring the ox. Realizing that the eagle would eat the their entire meal, Loki hit it with a staff. The staff stuck to the eagle and to Loki’s hand, and the jotun flew back toward Jotunheim, dragging Loki behind him and bumping him on trees and boulders as he went. Loki realized he had been tricked and offered to do whatever Thjazi required of him. Thjazi tasked him with going back to Asgard and stealing Idunn and her apples of Immortality for him.
Loki went back to Asgard with Odin and Hoenir. He lured Idun out of Asgard with tales of a new kind of apple tree, and Thjazi, in eagle form, swooped down and carried her off. Eventually the gods began to age, and they noticed that Idun and her apples of immortality are missing. When they found out that Loki was the last one who was seen with Idun, they threatened him with bodily harm until he agreed to get her back. Loki borrowed Freya’s falcon cloak and flew to Jotunheim. He found Idun, changed her into a walnut, and flew back with her, with Thjazi hot on his heels. As Loki flew back into Asgard, the rest of the Aesir sent up a huge fire wall, which Thjazi then flew into and died.
Then, with this context, the story of Njord and Skadi begins:
Skadi, an accomplished hunter, learns that her father, Thjazi, has been killed by the Aesir. She packs up her weapons and storms up to Asgard’s walls, demanding retribution. The gods offer Skadi her choice of the hand in marriage of any of the Aesir present. She agrees to this but also demands that one of them must make her laugh. None succeed at this until Loki ties his balls to the beard of a nanny goat and hilarity ensues. At that point, even Skadi has to laugh.
However, the gods put a restriction on how Skadi was to chose her husband. She was only allowed to see his feet. She chooses the whitest, brightest feet, assuming that those feet must belong to Baldur, Odin and Frigga’s son and Asgard’s shining glory. Instead, she ended up with Njord, god of the sea and commerce, father of Freyr and Freya. They first went to live at her father’s home in Jotunheim. However, the howling of the wolves and the wind were too loud for Njord to sleep, and after nine nights they left. Next they went to his home at Noatun, but Skadi could not sleep there due to the loud crying of the seagulls, and flashing of the sun on the waves irritated her. They agreed to live separately, and parted amicably, and each at his or her own hall.