Anadolu Agency said today the suspects were detained in simultaneous raids in the city a day earlier. All six were foreign nationals, the agency said without specifying their nationalities.
Anadolu said one of the suspects had been in contact with the suicide bombers while the five others "acted jointly" with him or her.
Authorities have arrested 30 other suspects since the attack, including 14 foreign nationals.
Three militants armed with assault rifles and suicide bombs stormed Istanbul's Ataturk Airport on June 28.