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 |
| Sound | Masahiro Owada | Music Supervisor |
| Writing | Jukki Hanada | Screenplay |
| Visual Effects | Mei Isai | Key Animation |
| Visual Effects | Hiroyuki Takahashi | Animation Director |
| Production | Yoko Kogawa | Executive Producer |
| Visual Effects | Naoko Yamada | Key Animation |
| Directing | Noriyuki Kitanohara | Second Unit Director |
| Visual Effects | Shinpei Sawa | Key Animation |
| Visual Effects | Kohei Okamura | Animation Director |
| Visual Effects | Hidehiro Asama | Key Animation |
| Visual Effects | Eisaku Kawanami | Key Animation |
| Crew | Rina Miura | Special Effects |
| Art | Naoki Hosokawa | Background Designer |
| Visual Effects | Tatsunari Maruko | Key Animation |
| Visual Effects | Miku Kadowaki | Animation Director |
| Visual Effects | Kunihiro Hane | Key Animation |
| Visual Effects | Shiho Morisaki | Key Animation |
| Visual Effects | Ryo Miyaki | Key Animation |
| Visual Effects | Tamami Tokuyama | Key Animation |
| Production | Yoko Hatta | Executive Producer |
| Production | Shunji Inoue | Executive Producer |
| Production | Yota Tsuruoka | Executive Producer |
| Visual Effects | Seiichi Akitake | Animation Director |
| Visual Effects | Mariko Takahashi | Key Animation |
| Visual Effects | Minoru Ota | Key Animation |
| Visual Effects | Nobuaki Maruki | Key Animation |
| Visual Effects | Kohei Okamura | Key Animation |
| Visual Effects | Tatsunari Maruko | Animation Director |
| Visual Effects | Ryosuke Shirakawa | Key Animation |
| Visual Effects | Yoshiko Tanaka | Compositing Artist |
| Visual Effects | Teru Matsumoto | Compositing Artist |
| Visual Effects | Noriyuki Kitanohara | Key Animation |
| Directing | Shinpei Sawa | Second Unit Director |
| Visual Effects | Yuko Myouken | Key Animation |
| Visual Effects | Fumie Okano | Key Animation |
| Visual Effects | Tatsuya Satou | Key Animation |
| Visual Effects | Kayo Hikiyama | Key Animation |
| Visual Effects | Takuya Yamamura | Key Animation |
| Visual Effects | Yuki Yokoyama | Key Animation |
| Visual Effects | Yusuke Miyahara | Key Animation |
| Art | Mutsuo Shinohara | Art Designer |
| Directing | Taichi Ogawa | Second Unit Director |
| Visual Effects | Maiko Hado | Key Animation |
| Art | Shouko Ochiai | Background Designer |
| Visual Effects | Ryouhei Muta | Key Animation |
| Visual Effects | Sayaka Watanabe | Key Animation |
| Visual Effects | Saeko Fujita | Key Animation |
| Visual Effects | Sumire Kusano | Key Animation |
| Visual Effects | Futoshi Nishiya | Supervising Animation Director |
| Visual Effects | Yuki Tsunoda | Animation Director |
| Visual Effects | Kota Sato | Key Animation |
| Art | Shingo Kasai | Background Designer |
| Art | Hiroyuki Takahashi | Prop Designer |
| Visual Effects | Seiichi Akitake | Key Animation |
| Visual Effects | Yoshinori Urata | Key Animation |
| Visual Effects | Rie Sezaki | Key Animation |
| Directing | Minoru Ota | Second Unit Director |
| Visual Effects | Hiroshi Karata | Key Animation |
| Art | Nozomi Oishi | Background Designer |
| Visual Effects | Rin Yamamoto | 3D Animator |
| Visual Effects | Yuji Shibata | 3D Animator |
| Visual Effects | Yuki Tsunoda | Key Animation |
| Visual Effects | Kazumi Ikeda | Animation Director |
| Visual Effects | Kyohei Ando | Key Animation |
| Visual Effects | Chiharu Kuroda | Key Animation |
| Visual Effects | Kakeru Isokawa | Key Animation |
| Art | Tomoki Hiraishi | Background Designer |
| Art | Aki Yamatogi | Background Designer |
| Art | Ikuko Tamine | Background Designer |
| Visual Effects | Mitsuki Takaki | 3D Animator |
| Sound | Eiko Morikawa | Sound Effects |
| Art | Atsushi Kiyama | Background Designer |
| Art | Miyuki Hiratoko | Background Designer |
| Visual Effects | Norihiro Tomiita | 3D Director |
| Art | Marie Kitai | Background Designer |
| Visual Effects | Kohei Funamoto | Compositing Artist |
| Visual Effects | Kazuki Ueno | Compositing Artist |
| Production | Shinichi Nakamura | Producer |
| Art | Yukiko Takeuchi | Background Designer |
| Art | Lee Cheon-bok | Background Designer |
| Art | Kouji Maruyama | Background Designer |
| Visual Effects | Sae Sawada | Key Animation |
| Visual Effects | Seiya Kumano | Key Animation |
| Visual Effects | Aoi Matsumoto | Key Animation |
| Visual Effects | Chika Kamo | Key Animation |
| Visual Effects | Momoka Yoshizaki | Key Animation |
| Visual Effects | Akiyo Takeda | Color Designer |
| Art | Mao Takayama | Background Designer |
| Art | Kim Ji-hee | Background Designer |
| Production | Eharu Ohashi | Producer |
| Visual Effects | Nobuaki Maruki | Animation Director |
| Visual Effects | Sana Suzuki | Key Animation |
| Visual Effects | Ami Kuriki | Key Animation |
| Visual Effects | Miho Takechi | Key Animation |
| Art | Sayaka Ichiyama | Background Designer |
| Art | Shiori Yamazaki | Background Designer |
| Art | Momoka Hase | Background Designer |
| Production | Shigeru Saito | Producer |
| Directing | Yasuhiro Takemoto | Second Unit Director |
| Visual Effects | Taichi Ogawa | Key Animation |
| Visual Effects | Shouko Ikeda | Supervising Animation Director |
| Visual Effects | Yuko Myouken | Animation Director |
| Directing | Naoko Yamada | Second Unit Director |
| Visual Effects | Nami Iwasaki | Key Animation |
| Visual Effects | Yurika Ono | Key Animation |
| Visual Effects | Tomomi Sato | Key Animation |
| Art | Mikiko Watanabe | Background Designer |
| Art | Shuuya Uchiyama | Background Designer |
| Production | Megumi Suzuki | Producer |
| Art | Sagako Itakura | Background Designer |
| Sound | Shigeru Saito | Music Producer |
| Production | Yoshifumi Yarimizu | Producer |
| Visual Effects | Taira Yamaguchi | Key Animation |
| Art | Shuhei Okude | Background Designer |
| Art | Park Jung-ah | Background Designer |
| Visual Effects | Hiroki Ueda | Compositing Artist |
| Art | Lee Mi-jin | Background Designer |
| Art | Kazuki Ikeda | Background Designer |
| Art | Etsuko Abe | Background Designer |
| Art | Tatsuya Ishihara | Storyboard Artist |
| Sound | Yasushi Nagura | Sound Recordist |
| Production | Areum Han | Production Manager |
| Production | Mika Cho | Production Manager |
| Production | Takahisa Fujita | Production Manager |
| Production | Anna Asano | Production Manager |
| Production | Yotaro Sato | Production Manager |
| Production | Anna Yamada | Production Manager |
| Production | Keisuke Yokota | Production Manager |
| Production | Saki Yasuda | Production Manager |
| Writing | Ayano Takeda | Novel |
| Directing | Tatsuya Ishihara | Director |
| Editing | Kengo Shigemura | Editor |
| Sound | Akito Matsuda | Original Music Composer |
| Camera | Kazuya Takao | Director of Photography |
| Production | Takuma Nagao | Publicist |
| Art | Mutsuo Shinohara | Art Direction |
| Visual Effects | Shouko Ikeda | Character Designer |
| Sound | Yota Tsuruoka | Sound Director |
