The two-and-a-half-year loan deal still allows Barcelona to sell Turan during that period if a club makes an offer for him.
Barcelona have confirmed that Arda Turan is set to leave the club and join Istanbul Basaksehir on a two-and-a-half year loan deal.
Spanish newspaper Sport last week estimated it cost Barca one million euros for each appearance made by Turan, taking into account an annual salary reported to be 8 million euros a year.
Turkey global Turan moved to the Camp Nou from Atletico Madrid in the summer of 2015, but Barca's transfer embargo meant he was prevented from registering for the club until January 1, 2016.
During his time at Camp Nou, Arda won medals in LaLiga, the Copa del Rey and the Supercopa de Espana, but failed to hit the same high standards he produced at Atleti.
The club's president Goksel Gumusdag took charge of the negotiations, finally striking a deal with Barca's CEO Oscar Grau late in the week ahead of Saturday's announcement.
"This is not just a transfer for Basaksehir, but a transfer for Turkey".
But Turan, 30, has opted to return to his homeland to seek more regular first team football.
Turan is a household name in his home country, where his personal life is followed as closely as his exploits on the field.
'Meanwhile, Istanbul Basaksehir will reserve the right to buy the player from Barcelona'.