Ahvaz has regular flights from Tehran, Isfahan, and other major Iranian cities — the airport is south of the city centre, about 15 minutes by taxi. By train, Ahvaz sits on the main line connecting Tehran to Khorramshahr, with daily services from Tehran taking around 12 hours overnight. Long-distance buses from Tehran, Isfahan, and Shiraz are frequent and cheap; the bus terminal is on the eastern edge of the city.
If you are coming to visit the archaeological sites of Khuzestan rather than Ahvaz itself, you can also enter the region via Dezful or Andimeshk to the north, which have their own transport connections.