The Ligue 1 side’s sporting director, Leonardo, confirmed the departure of the club icons, whose contracts are set to expire.
Cavani, who joined PSG from Napoli in 2013, has hit a club-record 200 goals in all competitions from 301 appearances, while Thiago has appeared 310 times for the club.
“It was a difficult decision to make, they are players who made their mark on the club’s history,” Leonardo admitted to Le Journal du Dimanche.
“We had to make a decision based on logic.”
Both players will be involved in the Champions League campaign, which is expected to be concluded in August.
PSG qualified for the quarter-finals after eliminating Borussia Dortmund in the last 16.
After more than three months off during the COVID-19 crisis, the team will resume training on June 22, with Neymar expected to be on the ground after returning from Brazil on Saturday.
Leonardo said he expected the Brazil forward to be at the club next season.
“Nothing tells us otherwise,” said Leonardo when asked if Neymar and France striker Kylian Mbappe would still be there next season.
“They still have two years on their contracts and we’re more thinking about the future with them. We want to go forward.”
PSG were crowned champions on April 30 when the league brought the season to an end as part of the country’s efforts to contain the novel coronavirus.
Reuters contributed to this report