The league will be contested by 18 teams. This is made up of fifteen teams from the previous season and three teams promoted from
Liga 2. Three teams were relegated at the end of the previous season.
PSIS were the first to be relegated on 11 May 2025 after
Semen Padang draw with
Persebaya in an away match during matchweek 32. The result ended PSIS's seven-season stay in the first-tier. The other two teams to be relegated were
PSS and
Barito Putera with the results of each match in final matchweek. Despite winning over
Madura United, PSS were relegated after six seasons in the top tier.
Barito Putera win over PSIS on the final day did not keep them in the division for the first time in 12 years. Three teams were promoted from Liga 2.
Bhayangkara Presisi secured promotion following a win over
Persijap in matchweek 5 of Group Y in the championship round
PSIM were promoted following a win over
PSPS in matchweek 6 of Group X in the championship round. This season marks PSIM's return to the top tier after 18 years.
Persijap won the divisional promotion play-off in a game against PSPS. This marked Persijap's return to the top tier after 10 seasons of absence, including two seasons in the third tier. Starting from this season,
I-League announced an increase in the foreign player quota to a maximum of 11 players per club. However, only 9 foreign players are allowed to be registered in the matchday squad, with a maximum of 7 in the starting eleven and 2 on the bench. ==Teams==