The Fandom Post is reporting that Tubi TV has added the Sound! Euphonium The Movie: Our Promise: A Brand New Day anime film to its service. It is available in its English dubbed form.
The film debuted in Japanese theaters on April 19, 2019, and was released as a Blu-ray/DVD combo in the United States on June 2, 2020.
The story of Sound! Euphonium is described as:
It’s finally time for Kumiko Oumae to enter high-school and begin the next chapter of her life. Being a member of concert band all throughout the lower-grades, one of her first orders of business is scouting out the band at her new school to see how they compare to what she has grown up with. After actually hearing them, however, Kumiko is… surprised to say the least. The concert band of Kitauji High School is terrible, especially compared to the borderline-national’s band Oumae was in earlier. Students in the band have gotten lazy and fallen into a slump in which none of them particularly care about the band’s future. But all of that changes when they meet their new teacher, professional composer Noboru Taki.
Source: The Fandom Post