Like other Saloon films, the film was hand-drawn. The film began production soon after the release of The Secret of Kells (2009), premiered at the 2014 Toronto International Film Festival on 6 September in the "TIFF Kids" programme. The film had a limited release in certain countries, but received acclaim and was nominated for the Academy Award for Best Animated Feature at the 87th Academy Awards in 2015.
Conor, a lighthouse keeper, lives on an island with son Ben, his pregnant wife Bronagh, and sheepdog Cú. Bronagh disappears late one night, presumably dying after childbirth, leaving behind daughter Saoirse (pronounced SIHR-shuh).
Six years later, Conor is broken, Saoirse is mute, and Ben is antagonistic towards Saoirse, blaming her for Bronagh's disappearance. On her birthday, she is visited by their grandmother, "Granny". That night, Ben scares Saoirse with a story of Mac Lir and his mother Macha, the Owl Witch, who stole his feelings and turned him to stone. Later, Saoirse plays a seashell horn given to Ben by their mother, leading her to a white sealskin coat in Conor's closet. She wears the coat and walks to a group of seals in the sea, revealing her as a selkie. After swimming, she is found by Granny, who insists upon taking the children to the city. Conor reluctantly agrees despite Ben's protests, and locks the coat in a chest, throwing it into the sea.
On Halloween, Saoirse plays the shell, alerting Færie to her. She and Ben attempt to go home, but encounter the Færie, hopeful that Saoirse will allow them to go to Tír na nÓg. However, they are attacked by Macha's owls, turning the Færie to stone. They take a country bus, where they run into Cú, who had followed them. However, Saoirse is growing ill. They come across a sacred well that Saoirse dives into. Ben follows and meets the Great Seanachaí: They learn that she was kidnapped by Macha, and that she is mute because she needs the coat, otherwise she will die. He gives Ben one of his hairs that will lead him to Macha. As he follows the hair, it shows him that Bronagh - a selkie herself - had to return to the ocean when Saoirse was born.
Ben then meets Macha, who explains that when Mac Lir suffered from a broken heart, she turned him into an island near their home. She is determined to do the same for everyone, even herself. Ben manages to rescue Saoirse, giving Macha back her feelings and allowing her to recognize that taking away feelings doesn't help. She helps them fly them back home, and Conor attempts to take Saoirse to a hospital; simultaneously, Granny is near the island to find them. Ben dives into the sea in search of Saoirse's coat, and recovers it with the seals and Conor. The group is then washed up on Mac Lir's island, where Saoirse's health is fully restored and she sings the song of the sea. The Færie rise and travel to Mac Lir and he emerges with Macha and his dogs as they head to Tír na nÓg.
Bronagh appears preparing to depart with Saoirse, but Ben pleads to let her stay with them. Since she is half-human, the choice rests with Saoirse, who elects to remain behind with her father and brother, even if it means giving up her selkie powers. Bronagh takes her coat and departs. After a tearful goodbye, the Faeries depart across the sea, and Ben and his family happily return home to their island, where Granny finally arrives, and decides the children can stay with their father. Ben and Saoirse reconcile and become friends.David Rawle as Ben
Brendan Gleeson as Conor and Mac Lir
Fionnula Flanagan as Granny and Macha
Lisa Hannigan as Bronagh; Ben and Saoirse's mother
Lucy O'Connell as Saoirse
Jon Kenny as Ferry Dan and The Great Seanachaí
Pat Shortt as Lug
Colm Ó Snodaigh as Mossy
Liam Hourican as Spud and Bus Driver
Kevin Swierszcz as Young Ben
Will Collins as Additional voices
Paul Young as Additional voices
The original music for the film was composed by Bruno Coulais, in collaboration with the Irish group Kíla. The film also features the voice of Lisa Hannigan and songs by Nolwenn Leroy. A soundtrack album, consisting of 25 songs from the film, was released digitally on 9 December 2014 by Decca Records.
Song of the Sea premiered at the 2014 Toronto International Film Festival on 6 September 2014 in the TIFF Kids program. Theatrically, it was released in France, Belgium and Luxembourg on 10 December 2014. It received a limited release in North America on 19 December 2014, which qualified it for an Academy Award nomination. It was released in Ireland on 10 July 2015.
The film has grossed CN¥15 million in China and US$857,522 in the United States and Canada.
Early reviews were overwhelmingly positive. Todd Brown, founder and editor of Twitch Film, gave a highly positive review of the film, saying that "a tale that weds absolutely gorgeous artwork with beautifully nuanced characters and a deep but natural rooting in ancient folk tales and magic, Song of the Sea has an assured and timeless quality to it. It is the sort of story that feels as though it always existed somewhere, just waiting until now to be told". "Song of the Sea is not about selling units, it's about story and heart and emotion and wonder and craftsmanship and because of that it becomes timeless, a beautiful piece of art that will delight audiences old and young and confirms what many suspected of Moore after Kells: The man's a master storyteller, and we can only hope he has many, many more stories to tell."
On review aggregator website Rotten Tomatoes, the film has a score of 99% and an average rating of 8.4/10 based on 77 reviews. It also has a score of 85 out of 100 on Metacritic from 24 reviews.
Writing in the Toronto Review, Carlos Aguilar said of the film: "Watching Song of the Sea it is easy to assert that this is one of the most blissfully beautiful animated films ever made. It is a gem beaming with awe-inspiring, heartwarming magic".
Sara Stewart from the New York Post said "If you want some real cinematic magic this holiday season, don’t miss this enchanting Irish film about a pair of siblings and a piece of Celtic folklore that turns out to be true".
An animator Ken Priebe found in the film a lot of influence of Hayao Miyazaki, in particular, the scene on the bus is similar to the scene on the train from Spirited Away, and the owl witch looks like Yubaba from the same film.