The 2023–24 Japan Rugby League One – Division 1 season is the thirteenth top flight league season played from December 2023 through to May 2024,[1] in the newly rebranded Japan Rugby League One.

The competition consisted of twelve teams, including one promoted team from Division 2, the Mie Heat.

It will consist of a round-robin fixture, before entering into a knockout style play-off for the final four teams.

Each team played a total of sixteen seasonal fixtures, plus additional play-off matches, including relegation play-offs.

All times Japan Standard Time (JST) (UTC+9) Black Rams Tokyo v Green Rockets Tokatsu Mie Heat v Shuttles Aichi Hanazono Liners v Urayasu D-Rocks Bracket