The Spain midfielder, 33, has made 669 appearances in 16 seasons, winning 31 trophies with Barca and three major tournaments for Spain.
Iniesta, who has been linked to a move to the Chinese Super League, has not said where he will play next season.
“I said I would never play against Barca so it is not going to be in Europe,” he said.
“We will know at the end of the season – there are still things to talk about.”
Iniesta has won the 2010 World Cup, Euro 2008 and Euro 2012 with Spain, as well as four Champions Leagues and eight La Liga titles – soon set to become nine – with Barcelona.
“It is a difficult day for me to be here saying goodbye when I’ve spent my whole life here,” he said in an emotional news conference watched by his family, team-mates and manager Ernesto Valverde.
Fighting back tears, he added: “A great deal of who I am, is down to Barca and La Masia – I am very thankful to them.
“I spoke to a lot of people – players, coaches – and I know what they want, but I tried to be honest with myself and the club.”\
