): Haruka Nanase, joined by Makoto Tachibana, looks for an apartment in Tokyo as he prepares to enter college.

Kisumi Shigino, whose uncle owns a rental agency, helps him lease an apartment close to a pool.

While visiting the apartment, Haruka and Makoto find a boy named Misaki, a young swimmer who was coached by the previous tenant, Nao Serizawa.

During the trip, Momotaro gets into a heated competition with the captain of Sofukan High School's swim team over a capybara plush toy.

Natsuya Kirishima, an alumnus of Sofukan High School and chaperone to their training camp, offers wise words to Sosuke over his shoulder injury.

On their way back Aiichiro and Momotaro give Rin and Sosuke two good luck charms as gifts.

): Rei Ryugazaki, Nagisa Hazuki, and Gou Matsuoka create a recruitment video for the swimming team for the upcoming school year.

While filming, Gou finds an old recruitment manual left from the previous members of the club with the strategy "PKH East", which they believe to be resourceful for the video.

He discovers that Momotaro plans to challenge him to a relay along with his older brother, Seijuro Mikoshiba, making him even more concerned about losing Gou.

Kyoto Animation announced that a "new screen project" had been green-lit in a promotional video for the home release of High Speed!

[13] Jacob Chapman from Anime News Network cited the film's strengths as an "enjoyable comedy" that helps "ease fans gently into season three", but claimed that the film seemed like an original video animation and the change in director from Hiroko Utsumi to Eisaku Kawanami greatly affected the "atmosphere, drama, and fan service.

"[14] Nick Creamer from Anime News Network praised it for integrating the comedic style of the show's first season, but felt that the narrative was not cohesive.

[17] The opening theme song, "Free-style Spirit", was performed by Style Five, which consists of the voice actors for Haruka, Makoto, Nagisa, Rei, and Rin.

", was performed by The Merry Friends of Iwatobi (岩鳶町のゆかいな仲間たち, Iwatobi-cho no Yukai na Nakama-tachi).

[19] Both songs were released as a double-A side single on November 8, 2017, which debuted on Oricon at #19 and charted for 5 weeks.