In the main series
Tracey's Marill debuted in The Crystal Onix. It was friendly and had a nurturing instinct.
Lyra's main Pokémon was her Marill, which debuted in An Egg Scramble!.
A Marill with the ability to Sing appeared in PK18, PK19, PK20, and PK21. Its singing would cause Meowth and Team Rocket's other Pokémon to go to sleep, which would make it angry and puff up, much like Jigglypuff.
In Pikachu's Vacation, a Marill was part of a group of troublemakers with Cubone, Snubbull, and Raichu at the Pokémon Theme Park, duking it out with Pikachu and his friends until they came to a truce.
In For Crying Out Loud, Wilhomena owns a Marill that was a crybaby. It got lost in a forest with Misty. It reappeared in a flashback in the Japanese version of Gotta Catch Ya Later!.
In Right on, Rhydon, Pietra used a Marill to battle and ultimately catch a Rhydon that knew Surf in order to help her with her digging project.
In A Family That Battles Together Stays Together!, a Marill was one of the Water-type Pokémon brought home by Lola. She used it against Flint's Golem in a battle for the title of Gym Leader of the Pewter Gym. It won using the waves of the water to Surf against Golem. It reappeared in a fantasy in Grating Spaces!.
In Candid Camerupt, Vivi Winstrate owns a Marill. It battled Max, who wanted to go easy on it because he had developed a crush on Vivi. However, Ash's Corphish refused to abide with Max and defeated Marill anyway.
In Three Sides to Every Story!, Lulu's Marill gained the romantic attention of Piplup and an Elekid, but it only reciprocated Elekid's feelings.
In The Power of Us, a Marill was following Harriet around.
In Bye Bye Psyduck, Misty's flashback featured a Marill.
In Tricks of the Trade, a Marill was at the Pokémon Swap Meet in Palmpona.
In The Fire-ing Squad!, five Marill competed as a team in the Fire and Rescue Grand Prix.
A Marill appeared in a fantasy in The Totodile Duel.
In Love, Totodile Style, Trixie uses a Marill for her circus.
In Hook, Line, and Stinker, a Trainer's Marill competed in the annual Seaking Catching Competition.
In Beauty and the Breeder, two Marill belonging to different Pokémon Breeders competed in a Pokémon breeding competition, with one of them being the first entrant.
In Around the Whirlpool, a Marill was seen when Brock approached its Trainer for advice as part of his Breeder training.
In Octillery The Outcast and Dueling Heroes, a Trainer's Marill competed in the Whirl Cup.
In Nice Pryce Baby, Team Rocket's fantasy featured a Marill.
In Journey to the Starting Line!, multiple Marill were at Professor Oak's Laboratory.
A Marill appeared in A Ruin with a View.
A Coordinator's Marill appeared in All Things Bright and Beautifly!.
In Gonna Rule The School!, the Pokémon Trainers' School lent a Marill to the school's underage students for use in lessons.
In Abandon Ship!, a Marill bounced by with two Azurill on the Abandoned Ship.
A Coordinator's Marill appeared in Pros and Con Artists.
A Coordinator's Marill appeared in Disguise Da Limit.
In A Double Dilemma, a Marill was living in North Petalburg.
In Lights, Camerupt, Action!, a Marill was an actor in one of Elijah's movies.
A Coordinator's Marill appeared in Mean With Envy.
In The Ribbon Cup Caper, a Marill was at the S.S. St. Flower's Pokémon Center.
In Hi Ho Silver Wind! and Deceit and Assist, a Coordinator's Marill competed in the Hoenn Grand Festival.
A Marill appeared in a fantasy in The Right Place and the Right Mime.
In The Saffron Con, a Coordinator's Marill competed in the Saffron Contest.
A Marill appeared in Weekend Warrior.
In On Olden Pond, a Marill was at the lake.
A Trainer's Marill appeared in Curbing the Crimson Tide!.
In What I Did for Love!, a Coordinator's Marill competed in the Mulberry Contest.
A Coordinator's Marill appeared in New Plot, Odd Lot!.
In the beginning of Pokémon Ranger and the Temple of the Sea, a Marill and its evolutionary relatives put out a forest fire while under the control of Solana's Capture Styler.
A Marill appeared in The Rise of Darkrai.
In Pruning a Passel of Pals!, a Coordinator's Marill competed in the Wallace Cup.
A Marill appeared in One Team, Two Team, Red Team, Blue Team!.
In Another One Gabites the Dust!, a Coordinator's Marill competed in the Performance Stage of the Chocovine Contest.
A Marill appeared in Sticking With Who You Know!.
In The Fleeing Tower of Sunyshore!, a Marill was at the Sunyshore City Pokémon Center.
In Coming Full-Festival Circle!, a Marill listened as Nando was playing his music.
A Marill appeared in League Unleashed!, under the ownership of a boy.
A Marill appeared in Zoroark: Master of Illusions.
A Trainer's Marill appeared in Curtain Up, Unova League! and Lost at the League!.
A Marill appeared in Mewtwo — Prologue to Awakening.
A Marill appeared in Kalos, Where Dreams and Adventures Begin!.
A Marill appeared in Lumiose City Pursuit!, Mega-Mega Meowth Madness!, Day Three Blockbusters!, and Battling With a Clean Slate!; and in flashbacks in Mega Evolution Special I, and Garchomp's Mega Bond! at Professor Sycamore's lab.
A Marill appeared in A Blustery Santalune Gym Battle!.
Two Marill appeared in A Jolting Switcheroo!.
A Marill appeared in Awakening the Sleeping Giant.
A Marill appeared in Going for the Gold!.
A Marill appeared in A Battle by Any Other Name!.
A Marill appeared in The Bonds of Evolution!.
A Marill appeared in Heroes - Friends and Faux Alike!.
A Marill appeared in a flashback or a fantasy in The Forest Champion!.
A Trainer's Marill attended the Pokémon Summer Camp in Foggy Pokémon Orienteering!.
A Marill appeared in Dreaming a Performer's Dream!.
In A Showcase Debut!, a Performer's Marill competed in the Coumarine City Showcase.
A Marill appeared in A Fashionable Battle!.
A Trainer's Marill appeared in a video in Rivals: Today and Tomorrow!.
A Marill appeared in Hoopa — The Mischief Pokémon.
A Trainer's Marill appeared in Performing with Fiery Charm!.
In Pikachu and the Pokémon Music Squad, four Marill were living in the forest.
In Adventures in Running Errands!, Chespin fell in love with a Marill riding on a bike with its Trainer, but Bunnelby grabbed its paw when it tried to chase them.
A Trainer's Marill appeared in A Performance Pop Quiz!.
A Marill appeared in Mega Evolution Special IV.
In The Legend of the Ninja Hero!, two Marill were residents of the Ninja Village.
In Party Dancecapades!, a Trainer's Marill attended Monsieur Pierre's dance party.
A Trainer's Marill appeared in Master Class is in Session!.
In Volcanion and the Mechanical Marvel, a wild Marill was living on Nebel Plateau.
A Trainer's Marill appeared in Valuable Experience for All!.
A Marill appeared in a flashback in The Legend of X, Y, and Z!.
Two Trainers' Marill appeared in The Power of Us.
A Trainer's Marill appeared in Turning the Other Mask!.
A Trainer's Marill appeared in a flashback in Battling Besties!.
A Trainer's Marill appeared in The Sinnoh Iceberg Race!.
A Trainer's Marill appeared in Finding a Legend!.
|| Ash's Pokédex
|| Marill, the Water Mouse Pokémon. Its sensitive ears can detect distant sounds and the round rubbery tip on its tail can expand and contract, assisting Marill in the water.
|| Dawn's Pokédex
|| Marill, the Aqua Mouse Pokémon. The tip of its tail floats in water, so it can swim in any current no matter how rough.
|| Dawn's Pokédex
|| Marill, the Aqua Mouse Pokémon. Its floating tail allows it to remain steady against the strongest of water currents.
In the Pokémon Masters Animated Trailer
In the Pokémon Masters Animated Trailer, a Trainer's Marill was in a Pasio town square.