2025–26 Japan Rugby League One – Division 1
| 2025–26 Japan Rugby League One – D1 | |
|---|---|
| Countries | Japan |
| Number of teams | 12 |
| Date | 13 December 2025 – 7 June 2026 |
| Matches played | 117 |
| Official website | |
| league-one | |
The 2025–26 Japan Rugby League One – Division 1 (Japanese: NTTジャパンラグビー リーグワン2025–26), known as the NTT 2025–26 Japan Rugby League One for sponsorship reasons, will be the fifth season of the Japan Rugby League One and the 22nd season in top-flight Japanese rugby. The season begins in December 2025 and ends in June 2026 with teams placed in the Play-offs and Relegation play-offs rounding out the season. The teams remained unchanged from the previous season (2024–25) as both teams in the relegation zone (Honda Heat, Urayasu D-Rocks) defeated the top two Division 2 teams over two-legs.
Toshiba Brave Lupus are the defending champions, having won their seventh title last season 18–13 against the Kubota Spears.