All In & The Hardest Thing

The two-part series finale of Amphibia consisted of the show's third season's 17th and 18th episodes, the 57th and 58th episodes overall, and the 105th and 106th segments overall: "All In" and "The Hardest Thing". Both episodes were directed by Roxann Cole and Joe Johnston. "All In" originally aired on Disney Channel on May 7, 2022, with "The Hardest Thing" airing the following week. Both episodes garnered 0.35 million viewers when they premiered, with the first part garnered a 0.10 rating, and the second part a 0.08 rating in the 18-49 demographics.

"All In" revolves around Anne, Sasha, and their allies trying to stop King Andrias and Darcy (who is Marcy being controlled by the Core) from conquering Earth, while "The Hardest Thing" revolves around Anne, Sasha, and Marcy trying to save Amphibia from being destroyed by the Core, which has taken control of the moon and is trying to crash it onto Amphibia's surface.

Both episodes, "All In" and "The Hardest Thing", received critical acclaim from both audiences, critics, and fans of the show alike, with strong praise going towards its fluid animation, voice acting, emotional weight and tone, writing, action sequences, cultural references, positive influential message, musical score, character development, LGBTQ representation, scale and cinematography, with many calling both episodes an epic, perfect, and bittersweet conclusion to the mature coming-of-age themes and character arcs of the show.