Chiang Mai International Airport has quite a few car rental agencies available on site. Options include Avis, Sixt, Budget, Tipoa and CM Airport Car Rent. A number of agencies are also scattered around the periphery of the airport including North Wheels, Europcar and an additional Budget location.
You'll find the largest range of car rental options at or near the airport. There are a small number of agencies to the south in the city, mostly local agencies.
Driving Near Chiang Mai International Airport
Chiang Mai International is located just north of the center of the city. The main roads going south are Highways 108 (which heads southwest) and 106 (which heads southeast). You can also connect to Highway 11 which is the quickest and most direct way south to Lamphun.
Chiang Mai is the busiest city in northern Thailand and there is usually a good amount of traffic to and from the airport. Motorbikes are the preferable way to get around the area if the weather is not too rainy, but it's important to have prior experience with them before hitting Chiang Mai roads as it's a very chaotic place to try and learn how to ride.
There are some significant differences between driving in the United States and driving in Thailand, and it's important to understand them to avoid accidents. Thai drivers are generally polite and considerate, but some road customs are very different. Red and green lights function the same way, but if the red light is exclusively for a pedestrian crosswalk, you're expected to go on red if no one is actually crossing. There also isn't really a custom of passing on the left or slow lanes on the right; Thai drivers will pass on either side with no particular driving pattern. Thai drivers are also aggressive, but it's not meant as disrespect. Rather than signaling they'll tend to edge their vehicle in a direction to let other drivers know what they're about to do.
Gas Stations Near Chiang Mai International Airport
There are quite a few gas stations near the airport, including a couple of Shell stations. It's not a bad idea to fill up there, as they become more infrequent as you head south. Unless you're heading south on Highway 11, that is, as there are a number of stations along its length. If you're taking Highway 1001 or 107 north, you'll also find a few stations scattered along the way.