Mayre Griffiths, nicknamed Trot, is a small girl living on the coast of California, her close friend and companion is Cap'n Bill, formerly her father's employer and now a retired seaman with a wooden leg. As they walk along the beach one day, Trot wishes that she could see a mermaid. Nearby mermaids overhear her, and grant her wish, appearing to her and the Cap'n the next day. The mermaids explain that they are "sea fairies," and offer the girl a chance to experience their world. Trot is eager to go; Bill is not, but is too loyal to let Trot go by herself. Magically transformed, the two embark on an underwater adventure.
The two see amazing sights in the domain of King Anko and Queen Aquareine including an octopus who is mortified to learn that he is the symbol of the Standard Oil Company. They also encounter a villain called Zog the Magician, a monstrous hybrid of man, animal, and fish. Zog and his sea devils capture Trot and Cap'n Bill and hold them prisoner. The two protagonists discover that many sailors who are thought to have drowned have actually been transformed into zombie-like gilled slaves by Zog. Trot and the Cap'n survive Zog's challenges, and the villain is eventually defeated by the forces of good. Trot and Cap'n Bill are returned to human form at the end of their undersea adventure.
Baum had attempted to close the Oz series the previous year: in the brief concluding chapter of The Emerald City of Oz (1910), Dorothy Gale writes to the author to explain that "You will never hear anything more about Oz, because we are now cut off forever from all the rest of the world." Baum was tired of Oz, and wanted to tell new and different stories.
Baum later resumed the Oz series, and eventually Trot and Cap'n Bill were brought into the series when they emigrated to the Land of Oz in The Scarecrow of Oz.
Many readers and critics have observed that Baum's Oz is a matriarchy, dominated by female figures of power and virtue. Baum biographer Katharine Rogers has noted that King Anko in Sea Fairies is a rare example of a benevolent father figure in Baum's work.
The public did not greet The Sea Fairies as enthusiastically as Baum hoped; the book sold 12,400 copies in its first year on the market, where Emerald City of Oz had sold 20,000. Baum's books went through a relative sales decline in the early and middle teens of the twentieth century, only to enjoy a resurgence late in the decade. Yet even then reception of The Sea Fairies was tepid, the book sold only 611 copies in 1918, when other Baum fantasies, both Oz and non-Oz, were selling in the thousands.
Baum continued his projected new series, however; the second volume, Sky Island, appeared in the following year, 1912.
- Cap'n Bill
- Charlie Griffiths (mentioned)
- Flippity (mentioned)
- Harry Hustle
- Inko (mentioned)
- Joe Weedles
- Mrs. Griffiths
- Mummercubble (mentioned)
- Prince of the Sea Devils
- Sea Devils
- Sea Serpents
- Singing Barnacles
- Snapping Eels
- Tom Atto
- Tommy Blimken
- Unko (mentioned)
- Patrick M. Maund. "Bibliographia Baumiana: The Sea Fairies." The Baum Bugle, Vol. 41 No. 1 (Spring 1997).
- Katharine M. Rogers. L. Frank Baum, Creator of Oz: A Biography. New York, St. Martin's Press, 2002.