Iraklio’s streets are narrow and chaotic so it's best to drop your vehicle in a car park (about €6 per day) and explore on foot. All the international car-hire companies have branches at the airport. Local outlets line the northern end of 25 Avgoustou and include Caravel, Motor Club and Sun Rise.
There are small taxi stands all over town but the main ones are at Bus Station A, on Plateia Eleftherias and at the northern end of 25 Avgoustou. You can also phone for one on 2814 003084.