Season 0 of Special Investigation Nine premiered on April 7, 2019.

Season 1 of Special Investigation Nine premiered on April 11, 2018.

Season 2 of Special Investigation Nine premiered on April 10, 2019.

Season 3 of Special Investigation Nine premiered on April 8, 2020.

Season 4 of Special Investigation Nine premiered on April 7, 2021.

New enemies appear to block the Tokusou 9. As in the past, the Tokusou 9 hold on to their belief that "the case will be solved at all costs" and put their all into solving cases.

Season 5 of Special Investigation Nine premiered on April 6, 2022.

Season 6 of Special Investigation Nine premiered on April 5, 2023.

Season 7 of Special Investigation Nine premiered on April 3, 2024.

Season 8 of Special Investigation Nine premiered on April 9, 2025.