Following eight successful seasons, Kashiwa Reysol bid farewell to the first division.
A similar fate befell V-Varen Nagasaki, who returned to J2 after their inaugural season in the top tier.
In addition, four teams experienced changes in their league status: Roasso Kumamoto and Kamatamare Sanuki exited J2, paving the way for the newly-promoted FC Ryukyu and Kagoshima United FC, both set to embark on their inaugural J2 season.
Players from J.League partner nations (Thailand, Vietnam, Myanmar, Malaysia, Cambodia, Singapore, Iran and Qatar) are exempt from these restrictions.
In the first two rounds of the 2019 J.League J1/J2 Play-Offs (2019 J1参入プレーオフ), if the score is tied after 90 minutes, no extra time is played and the winner is the team with the best J2 League ranking.