"I had many offers but Galatasaray was the number one," Sneijder told a news conference a day after hundreds of Galatasaray fans gave him a rapturous welcome on his arrival in Istanbul.
Reports said teams including Premier League Liverpool were also interested in the 28-year-old, who inspired Inter Milan to a Champions League, Serie A and Italian Cup treble in 2010 before helping the Netherlands finish World Cup runners-up.
"That was the best season so far in my life. The period after was a hard period," he said.
Sneijder struggled to maintain that success and was caught up in a contract dispute at Inter this season after failing to renegotiate his deal as the club sought to cut costs and being banished from the team.
The signing of Sneijder is a major coup for the Turkish league, which is more used to taking top players towards the end of their careers like Fenerbahce's Dutch forward Dirk Kuyt.
No financial details of the deal were immediately made public.
Turkish league leaders Galatasaray, who unlike Europa League contenders Inter are in the Champions League last 16, confirmed a deal was done after Sneijder announced the move on Sunday following days of pondering their offer.
Sneijder is expected to make his debut for the Super League champions in the derby against Besiktas on Jan. 27.