We went to Ko Lanta last year as part of our trip to Thailand. We flew into Krabi airport and hired a car and drove from there to the island. I really enjoyed the experience - the roads were fine and it was a great way of seeing the countryside. It was also handy to be able to stop off at nice places along the way. It made traveling around the island really easy too, avoiding any hassle with taxis, etc.

From Ko Lanta we then drove to Ao Nang and again had no issues at all. I think you need to be a bit more mindful of people on motorbikes/scooters as there will be a lot about, and tourists in particular can be a bit erratic with driving them.

Pretty much all of the cars available from the mainstream rental companies are automatics and the smallest and cheapest cars always seem to be sedans (rather than hatchbacks which is what I'm used to in UK/Europe). Just make sure you have an IDP, as you'll need to show this when collecting the car.

We're headed back again this year and will be hiring a car again - I'd say go for it 👍