While it has certain drawbacks, the bus is easily the most economical way to travel, and an adventure in itself. You can buy tickets and board at the major Bangkok public bus stations, or if you are stopping at Khao San Road, you can catch an overnight bus departing in the evening, to all southern destinations including Samui. You will stop very early in the morning at Suratthani, which is the mainland access city to Samui, where you will transfer to another bus for the trip to the ferry that crosses to the island.
Be aware that not all buses are the same. Spending a few baht more can make a significant difference in comfort. The most comfortable are probably the overnight “Super VIPs.” These air-conditioned double decker vehicles have toilets, seats that lean back quite far with leg rests at the bottom, and they also supply blankets for the journey. All buses stop at least once for refreshment, but little or no food or drink is served on board. An evening video is almost always shown on an overhead TV, and played at volumes that may make sleep difficult. However once the film ends around 10:00 pm, if you’re lucky, you may sleep through much of the night.
Khao San Road
Known to readers of every budget traveler’s guide, this little corner of the city is the first stop for many first-time travelers to Thailand who wish to spend a little time in Bangkok before continuing their journey. Catering especially to “backpackers”, most find Khao San Road a very hospitable place, and the easiest way to ease into the country with a minimum of culture shock. All the merchants and travel agents speak English, there are second-hand bookshops, coffee shops and inexpensive guesthouses, and many spend a few very comfortable days there chatting with travelers from all over the world before moving on to their next destination.
Tour buses run directly from Bangkok to Samui, and Samui to Bangkok via the vehicle ferry from Donsak in Suratthani Province.