"The delegation from our country will travel to Russia tomorrow to attend the aviation salon (MAKS)," Sputnik quoted a source in the Iranian foreign ministry as saying on Sunday.
"The exact delivery dates will be clarified upon the delegation's return," the source added.
Russian President Vladimir Putin decided in April to lift a ban on the S-300 missile system delivery to Iran. The ban had been introduced by former Russian president Dmitry Medvedev in 2010.
Under a contract signed in 2007, Russia was required to provide Iran with at least five S-300 defense system batteries.
In 2010, Medvedev cancelled the contract as he came under strong US and Israeli pressure not to go ahead with the sale of the weapons system, but his pretext was that the sale was covered by the fourth round of the UN Security Council sanctions against Iran.