List of Mermaid Man and Barnacle Boy episodes[]
| Title card | # | Title | U.S. airdate | U.S. viewers (millions)
|
|---|---|---|---|---|
 |
6a | "Mermaid Man and Barnacle Boy" (tr • ga) | August 21, 1999 | |
| SpongeBob and Patrick learn that their heroes are retired. | ||||
 |
20b | "Mermaid Man and Barnacle Boy II" (tr • ga) | March 3, 2001 | |
| SpongeBob wins a conch shell in a contest to summon his heroes. | ||||
 |
31a | "Mermaid Man and Barnacle Boy III" (tr • ga) | September 14, 2001 | |
| Mermaid Man and Barnacle Boy leave SpongeBob and Patrick in charge of the Mermalair, where they proceed to free the evil Man Ray and teach him how to be nice. | ||||
 |
45a | "Mermaid Man and Barnacle Boy IV" (tr • ga) | January 21, 2002 | |
| SpongeBob plays with Mermaid Man's shrink ray on his utility belt, but doesn't know how to turn things back to normal size. | ||||
 |
52b | "Mermaid Man and Barnacle Boy V" (tr • ga) | June 1, 2002 | |
| After being childishly teased for having "Boy" in his name, Barnacle Boy joins the dark side and a team emerges to try and stop him and his new allies. | ||||
 |
67b | "Mermaid Man & Barnacle Boy VI: The Motion Picture" (tr • ga) | October 7, 2005 | |
| SpongeBob and Patrick find out that a Mermaid Man and Barnacle Boy movie is in production and are using actors, so they make their own with the real heroes. | ||||
 |
82b | "Night Light" (tr • ga) | July 30, 2007 | |
| SpongeBob reads a scary book and develops a fear of the dark. | ||||
 |
94b | "Mermaid Man vs. SpongeBob" (tr • ga) | August 3, 2007 | |
| Plankton hypnotizes Mermaid Man and Barnacle Boy. | ||||
 |
113b | "The Card" (tr • ga) | November 28, 2008 | |
| Patrick finds a rare trading card and SpongeBob tries to protect it. | ||||
 |
114b | "Ditchin'" (tr • ga) | November 28, 2008 | |
| SpongeBob ditches boating school, then gets distracted on his way back. | ||||
 |
117a | "Shuffleboarding" (tr • ga) | February 16, 2009 | |
| SpongeBob and Patrick pretend to be their heroes at a shuffleboarding contest, but get sidetracked on the way home. | ||||
 |
135a | "Back to the Past" (tr • ga) | February 15, 2010 | |
| SpongeBob and Patrick accidentally change past events with Mermaid Man's time machine. | ||||
 |
135b | "The Bad Guy Club for Villains" (tr • ga) | February 15, 2010 | |
| SpongeBob and Patrick watch a lost episode of The Adventures of Mermaid Man and Barnacle Boy. | ||||
 |
163a | "Mermaid Man Begins" (tr • ga) | September 23, 2011 | |
| SpongeBob and Patrick learn the story of their heroes' origins. | ||||
 |
176a | "Super Evil Aquatic Villain Team Up is Go!" (tr • ga) | October 14, 2012 | |
| Plankton and Man Ray join forces and try to override the Krusty Krab. | ||||
 |
180a | "Patrick-Man!" (tr • ga) | October 27, 2012 | |
| Patrick becomes a superhero and plans to clean up Bikini Bottom. | ||||
 |
205b | "Mermaid Pants" (tr • ga) | October 29, 2016 | |
| When SpongeBob and Patrick play Mermaid Man and Barnacle Boy, it's all fun and games until their "sworn enemies" arrive. | ||||
 |
219a | "Man Ray Returns" (tr • ga) | September 30, 2017 | |
| When Man Ray rents Squidward's house for the weekend, it's up to SpongeBob and Patrick to stop his evil vacation. | ||||
 |
238a | "Appointment TV" (tr • ga) | October 28, 2018 | |
| The long-lost episode of "Mermaid Man" is finally showing on TV, but SpongeBob may not make it home in time to watch. | ||||
 |
247a | "Swamp Mates" (tr • ga) | April 11, 2020 | |
| Bubble Bass finds himself stranded with Patrick in a mysterious swamp, looking for a lost action figure. | ||||
 |
252b | "Dirty Bubble Returns" (tr • ga) | November 23, 2019 | |
| The newly reformed "Clean Bubble" takes a dishwashing job at the Krusty Krab, where he is tempted by the grime. | ||||
 |
277a | "Captain Pipsqueak" (tr • ga) | July 22, 2022 | |
| Plankton joins the League of E.V.I.L. in another attempt to steal the Krabby Patty secret formula. | ||||