Piper Curda returns to the Disney universe as the voice of Mabel Tanaka, a 19-year-old animal lover whose consciousness is transferred into a robotic beaver. Curda is best known for her starring roles on Disney Channel’s “I Didn’t Do It” and the hit sequel “Teen Beach Movie 2,” and has since appeared in “May December” and Netflix’s “American Pie Presents: Girls’ Rules.”

Bobby Moynihan voices King George, a beaver monarch whose authority is matched only by his insecurity. A longtime fixture of ensemble comedy, Moynihan spent nine seasons on NBC’s “Saturday Night Live” and has voiced characters in “Inside Out,” “DuckTales” and “Monsters University.”

Jon Hamm lends his voice to Mayor Jerry Generazzo, a slick and self-serving politician driven by greed and ambition. Hamm is best known for his Emmy-winning performance as Don Draper on AMC’s “Mad Men” and has recently appeared in FX’s “Fargo” and Apple TV+’s “The Morning Show,” as well as in films including “Top Gun: Maverick” and “Confess, Fletch.”

Kathy Najimy voices Dr. Sam, Mabel’s biology professor and the brilliant but morally conflicted scientist behind the hopping technology. Najimy’s career spans decades across film, television and animation, with credits including “Sister Act,” “Hocus Pocus,” “Veep” and the voice of Peggy Hill on Fox’s long-running animated series “King of the Hill.”

Dave Franco voices the Insect King, the calculating mate to the Insect Queen whose ambitions extend beyond his hive. Franco’s recent work includes Neon’s “Together,” Amazon MGM’s “Somebody I Used to Know,” “The Rental” and “Now You See Me 3.”

Eduardo Franco voices Loaf, a slow-moving but steadfast beaver. Franco broke out with his performance as Argyle on Netflix’s “Stranger Things” and has appeared in “Booksmart,” “American Vandal” and “The Afterparty.”

Aparna Nancherla voices Nisha, Dr. Sam’s loyal colleague at the top-secret lab. Before joining the animated world of “Hoppers,” the actor and comedian has leant her voice to characters in film and television shows including “The Great North,” “Bob’s Burgers,” “Orion and the Dark,” “Mira, Royal Detective” and “BoJack Horseman.” She has also written for “Late Night With Seth Meyers” and “Totally Biased With W. Kamau Bell,” amongst others.

Sam Richardson plays Conner, a cheerful biology graduate student in Dr. Sam’s lab. Richardson boasts a lengthy voice-acting resume, with credits on television shows like “Wylde Pak,” “Krapopolis,” “Bob’s Burgers,” “Sausage Party: Foodtopia” and “Velma.” His onscreen credits include “Veep” (as Richard Splett) and “Detroiters.”

Ego Nwodim voices the Fish Queen, described to be the boisterous, stern and formidable leader of the fish kingdom. Nwodim is best known for her work on “Saturday Night Live” from 2018, beginning with the show’s 44th season, to 2025, ending with the show’s 50th season. Nwodim also previously appeared in the TV series “Galactic War Room” and voiced characters for “Futurama,” “Baby Shark’s Big Movie” and “Diary of a Wimpy Kid Christmas: Cabin Fever.”

Nichole Sakura voices the Reptile Queens, a terrifying trio of almost identical snake sisters. Sakura is known for her roles as Cheyenne Tyler Lee in the NBC sitcom “Superstore,” Amanda in “Shameless” and Emily Davis in the horror video game “Until Dawn.”

Meryl Streep voices the Insect Queen, the most respected and feared member of the all-seeing and all-powerful Council. A three-time Academy Award winner, Streep’s most famous appearances include “Sophie’s Choice,” “Kramer vs. Kramer,” “The Iron Lady,” “The Devil Wears Prada” and “The Bridges of Madison County.” Streep holds the record for the most Academy Award and Globe nominations of any performer, with her career spanning over 64 films and 18 television projects.

Steven Purcell voices Amphibian King, a frog. A cartoonist, animator, game designer and voice actor, Purcell is best known for creating the media franchise “Sam & Max,” which includes a show, comic and game series. “Hoppers” isn’t Purcell’s first collaboration with Pixar; he co-wrote and co-directed “Brave” and developed “Cars on the Road,” a miniseries for the “Cars” franchise.

Bird King, a flighty, flippant goose, was voiced by Isiah Whitlock Jr. before he died at the age of 71 in December 2025. Whitlock was known for his roles in “The Wire” and other appearances in television shows and films including “Goodfellas,” “Chappelle’s Show,” “Pieces of April,” “Enchanted,” “Cars 3” and “Lightyear.” He was also known for his collaborations with director Spike Lee, which included “BlacKkKlansman,” “Da 5 Bloods,” “She Hate Me,” “25th Hour,” “Red Hook Summer” and “Chi-Raq.”

Vannessa Bayer voices Diane, a shark and feared assassin summoned to help the Council carry out their mission to stop Mayor Jerry. Bayer was a cast member on “Saturday Night Live” from 2010 to 2017, for which she was nominated for an Emmy Award. Bayer also previously appeared in “I Love That For You,” “Freakier Friday” and “Ibiza.”

Melissa Villaseñor plays Ellen, a menacing, though mostly just grumpy grizzly bear. The writer, comedian and actor is known for “Hubie Halloween,” “Ralph Breaks the Internet” and “Toy Story 4.” She also hosts the “Laughing With Myself” podcast.

Heidi Klum voices Diane in the German-dubbed version of “Hoppers.” Her character is referred to as Hai-Di, a pun on both Klum’s name and the German word for shark, “hai.” Klum is known for her career as a supermodel and later worked as a reality show judge on “Project Runway,” “Germany’s Next Top Model” and “America’s Got Talent.”