Kumiko is now a second year and one of the senior players of the euphonium section. With new underclassmen joining the concert band, Kumiko will have to learn new things in order to deal with awkward and difficult underclassmen. She and third-year trumpeter Tomoe Kabe have been chosen to lead the new underclassmen members. Among the new members to Kumiko's bass section are euphonist Kanade Hisaishi, whose appearances are deceiving; tuba player Mirei Suzuki, who cannot adapt to her new environment; tuba player Satsuki Suzuki, who wants to get along with Mirei; and double bassist Motomu Tsukinaga, who cannot talk about himself. Between the Sunrise Festival, chair placement auditions, and the competition, a number of problems quickly begin to arise.
Unfortunately the movie Sound! Euphonium the Movie – Our Promise: A Brand New Day is not yet available on HBO Max.
| Visual Effects | Joji Unoguchi | 3D Artist |
| Writing | Jukki Hanada | Screenplay |
| Visual Effects | Mei Isai | Key Animation |
| Sound | Masahiro Owada | Music Supervisor |
| Visual Effects | Taichi Ogawa | Key Animation |
| Production | Yoko Kogawa | Executive Producer |
| Directing | Taichi Ogawa | Second Unit Director |
| Visual Effects | Hiroyuki Takahashi | Animation Director |
| Art | Mutsuo Shinohara | Art Designer |
| Art | Hiroyuki Takahashi | Prop Designer |
| Directing | Noriyuki Kitanohara | Second Unit Director |
| Visual Effects | Shinpei Sawa | Key Animation |
| Directing | Minoru Ota | Second Unit Director |
| Visual Effects | Minoru Ota | Key Animation |
| Visual Effects | Nobuaki Maruki | Key Animation |
| Directing | Yasuhiro Takemoto | Second Unit Director |
| Production | Yoko Hatta | Executive Producer |
| Production | Yota Tsuruoka | Executive Producer |
| Directing | Shinpei Sawa | Second Unit Director |
| Production | Shunji Inoue | Executive Producer |
| Visual Effects | Noriyuki Kitanohara | Key Animation |
| Visual Effects | Naoko Yamada | Key Animation |
| Visual Effects | Yuki Tsunoda | Key Animation |
| Visual Effects | Kohei Okamura | Animation Director |
| Visual Effects | Kazumi Ikeda | Animation Director |
| Visual Effects | Eisaku Kawanami | Key Animation |
| Visual Effects | Futoshi Nishiya | Supervising Animation Director |
| Visual Effects | Yuko Myouken | Animation Director |
| Visual Effects | Kyohei Ando | Key Animation |
| Visual Effects | Sayaka Watanabe | Key Animation |
| Art | Naoki Hosokawa | Background Designer |
| Art | Sagako Itakura | Background Designer |
| Visual Effects | Kohei Funamoto | Compositing Artist |
| Visual Effects | Tatsunari Maruko | Key Animation |
| Visual Effects | Ryouhei Muta | Key Animation |
| Art | Shouko Ochiai | Background Designer |
| Art | Kouji Maruyama | Background Designer |
| Visual Effects | Kazuki Ueno | Compositing Artist |
| Visual Effects | Fumie Okano | Key Animation |
| Visual Effects | Chiharu Kuroda | Key Animation |
| Visual Effects | Yusuke Miyahara | Key Animation |
| Art | Lee Cheon-bok | Background Designer |
| Visual Effects | Rin Yamamoto | 3D Animator |
| Visual Effects | Takuya Yamamura | Key Animation |
| Visual Effects | Kakeru Isokawa | Key Animation |
| Art | Aki Yamatogi | Background Designer |
| Art | Atsushi Kiyama | Background Designer |
| Visual Effects | Hidehiro Asama | Key Animation |
| Visual Effects | Kota Sato | Key Animation |
| Crew | Rina Miura | Special Effects |
| Art | Miyuki Hiratoko | Background Designer |
| Art | Marie Kitai | Background Designer |
| Visual Effects | Norihiro Tomiita | 3D Director |
| Visual Effects | Yuko Myouken | Key Animation |
| Visual Effects | Seiichi Akitake | Animation Director |
| Visual Effects | Hiroshi Karata | Key Animation |
| Visual Effects | Mariko Takahashi | Key Animation |
| Visual Effects | Tatsuya Satou | Key Animation |
| Visual Effects | Kayo Hikiyama | Key Animation |
| Visual Effects | Chika Kamo | Key Animation |
| Art | Etsuko Abe | Background Designer |
| Visual Effects | Seiichi Akitake | Key Animation |
| Visual Effects | Kunihiro Hane | Key Animation |
| Visual Effects | Saeko Fujita | Key Animation |
| Visual Effects | Sumire Kusano | Key Animation |
| Visual Effects | Tamami Tokuyama | Key Animation |
| Art | Tomoki Hiraishi | Background Designer |
| Visual Effects | Yuji Shibata | 3D Animator |
| Production | Yoshifumi Yarimizu | Producer |
| Visual Effects | Nobuaki Maruki | Animation Director |
| Visual Effects | Sana Suzuki | Key Animation |
| Visual Effects | Yurika Ono | Key Animation |
| Art | Shuuya Uchiyama | Background Designer |
| Visual Effects | Teru Matsumoto | Compositing Artist |
| Visual Effects | Nami Iwasaki | Key Animation |
| Visual Effects | Ryo Miyaki | Key Animation |
| Visual Effects | Miho Takechi | Key Animation |
| Art | Mikiko Watanabe | Background Designer |
| Art | Momoka Hase | Background Designer |
| Art | Yukiko Takeuchi | Background Designer |
| Sound | Shigeru Saito | Music Producer |
| Directing | Naoko Yamada | Second Unit Director |
| Art | Ikuko Tamine | Background Designer |
| Art | Shuhei Okude | Background Designer |
| Art | Park Jung-ah | Background Designer |
| Visual Effects | Mitsuki Takaki | 3D Animator |
| Sound | Eiko Morikawa | Sound Effects |
| Visual Effects | Rie Sezaki | Key Animation |
| Visual Effects | Sae Sawada | Key Animation |
| Visual Effects | Momoka Yoshizaki | Key Animation |
| Art | Sayaka Ichiyama | Background Designer |
| Art | Kazuki Ikeda | Background Designer |
| Production | Shigeru Saito | Producer |
| Production | Eharu Ohashi | Producer |
| Visual Effects | Shouko Ikeda | Supervising Animation Director |
| Visual Effects | Yuki Tsunoda | Animation Director |
| Visual Effects | Yoshinori Urata | Key Animation |
| Visual Effects | Taira Yamaguchi | Key Animation |
| Visual Effects | Ami Kuriki | Key Animation |
| Visual Effects | Maiko Hado | Key Animation |
| Art | Shingo Kasai | Background Designer |
| Visual Effects | Hiroki Ueda | Compositing Artist |
| Visual Effects | Yuki Yokoyama | Key Animation |
| Production | Shinichi Nakamura | Producer |
| Visual Effects | Ryosuke Shirakawa | Key Animation |
| Visual Effects | Seiya Kumano | Key Animation |
| Visual Effects | Aoi Matsumoto | Key Animation |
| Visual Effects | Tomomi Sato | Key Animation |
| Visual Effects | Akiyo Takeda | Color Designer |
| Art | Shiori Yamazaki | Background Designer |
| Visual Effects | Kohei Okamura | Key Animation |
| Visual Effects | Tatsunari Maruko | Animation Director |
| Visual Effects | Miku Kadowaki | Animation Director |
| Visual Effects | Shiho Morisaki | Key Animation |
| Art | Nozomi Oishi | Background Designer |
| Art | Kim Ji-hee | Background Designer |
| Visual Effects | Yoshiko Tanaka | Compositing Artist |
| Art | Mao Takayama | Background Designer |
| Art | Lee Mi-jin | Background Designer |
| Production | Megumi Suzuki | Producer |
| Art | Tatsuya Ishihara | Storyboard Artist |
| Sound | Yasushi Nagura | Sound Recordist |
| Production | Areum Han | Production Manager |
| Production | Mika Cho | Production Manager |
| Production | Anna Yamada | Production Manager |
| Production | Yotaro Sato | Production Manager |
| Production | Keisuke Yokota | Production Manager |
| Production | Anna Asano | Production Manager |
| Production | Takahisa Fujita | Production Manager |
| Production | Saki Yasuda | Production Manager |
| Writing | Ayano Takeda | Novel |
| Directing | Tatsuya Ishihara | Director |
| Camera | Kazuya Takao | Director of Photography |
| Editing | Kengo Shigemura | Editor |
| Sound | Akito Matsuda | Original Music Composer |
| Production | Takuma Nagao | Publicist |
| Sound | Yota Tsuruoka | Sound Director |
| Visual Effects | Shouko Ikeda | Character Designer |
| Art | Mutsuo Shinohara | Art Direction |
