Travel within Thailand is relatively inexpensive and convenient. Thailand has an adequate infrastructure and an extensive network of train and bus lines, as well as domestic airports. The train routes basically connect the northern and southern regions. While not as extensive as the bus routes, the trains provide a more comfortable and scenic form of transport. You can ride the train as far north as Chiang Mai or Laos and as far south as Singapore.
A variety of buses connect all corners of Thailand, from deluxe VIP buses to tiny wooden benched country buses, and every class in between. Mini-vans cover extensive ground as well. While they tend to be faster than the big buses, they are tighter in space and are sometimes over-loaded. More out of the way places can often be reached by Songtaew (open air bus), which are very cheap, but slow yet run regularly.
Car and motorbike rental is also easy on the budget. A driving license from your home country or an International one is required for all vehicle hire. Keep in mind however, that the road accident rate in Thailand is extremely high. Expect the unexpected and be alert at all times! Thai law requires motorbike drivers to wear a helmet and car drivers and front passengers to wear seat belts. If renting a motorbike, helmets are required by the driver only. Ask for a second helmet if carrying a pillion passenger.
When opting for public transport especially when renting a Tuk-Tuk (small van taxi) or one of the motorbike taxis it is recommended that you agree on a price before you set off or you may end up paying more.
The many southern islands are reached by ferry or long-tail boat, or both. While most travel routes to these smaller islands provide a convenient combination of bus and ferry, it is also possible to charter your own water route utilizing the abundance of small long-tail boats to hop from island to island or beach to beach. Again, settle on a price before embarking.