If you need a SIM card during your travel, you can get your SIM card at the airport as soon as you arrive in Iran. The price of a SIM card with a credit of 20 GB will be less than 10$. (There is also a possibility to buy outside the airport).
Among the SIM card services in Iran, prepaid Irancell SIM card will be a better choice for travelers. Irancell network coverage is better and faster.
Generally, mobile Internet connection will be better and faster than hotels Wi-Fi connection.