Car rental in Heraklion?

My husband & I would like to rent a car for our day in Crete. We are docking at Heraklion. Should I book in advance or are there places at the cruise terminal? When I was looking online (priceline/kayak) I saw that a lot of them assumed I was coming in at the aiport.

We hired a car at Heraklion airport when we were on a land holiday. We booked it with a company that had been recommended to us. It was called The Best car hire. I'm sure you will find many car hire companies deliver to various destinations.

We booked in advance. We arrived by ferry.

Picked up the car at Avis. They have a booth in the port parking lot. Straight out the parking lot, up the street and you are at the main road on the island.