Visitors must declare all foreign currency upon arrival by filling out a customs declaration form. If you fail to declare your foreign currency, it may be subject to confiscation.
The Rial (ریال) is the official currency of Iran, however to save time in a high-inflation economy prices are sometimes quoted in Tomans (تومان). One Toman is equal to ten Rials.
As a general guide, written prices are given in rials and prices quoted in conversation are in Tomans. To confuse you even further, shopkeepers will often omit the denomination of high prices in conversation, so you may be told a jar of coffee costs 6 Tomans (meaning 6,000 Tomans or IR 60,000).
Remember that since Iran is still a cash economy you CAN NOT use your credit cards, ATM cards, Debit cards, Travel checks and etc. You need to have adequate cash with yourself.
It is essential that you have some ready cash at all times. Almost any currency is welcomed in Iran Exchange offices, ranging from Euro, US, $, Canadian $, Pound, Yen, Rupee and etc. You won’t have hard time to change your money. Try to carry larger bills which take smaller space. Try to exchange only as much as you would think you need for a few days and then go get some more money exchanges later on, if needed. Iranian Rial rate is changing frequently so please contact a trusty money changer or check on internet for currency converters
In average irrespective of hotel costs, you might need around 20 $ daily in overall personal expenditures. So exchanging a 100$ can goes a long way for you. Remember that for each 1$, for example, you are going to get 3 Iranian 10,000 Rails bills. So that is a lot of money in volume, maybe you need to have a waist hidden purse to put your money away.
You are highly encouraged to do your exchange in banks or Exchange offices. Money can be exchanged at the airport on arrival, too. There are branches of Melli, Tejarat, Sepah and Saman Bank in Imam Khomeini Airport. There are also some people that do offer exchange alongside the streets but do not change money on the street, as this practice is illegal in Iran.
Banks are open from Sunday to Wednesday from 07:30 to 15:00; Thursdays, 07:30 to 12:00; and closed on Fridays.