There are both government run air-conditioned and non air-conditioned busses that connect Bangkok, Phuket, Phang Nga, Trang, Hat Yai, and Surat Thani (Samui) to Krabi Bus Terminal. The bus from Bangkok’s Southern Bus Terminal to Krabi takes approximately 12 hours.
In addition to these busses, many private bus companies and travel agencies provide air-conditioned busses or vans to and from Krabi and these other provinces.
Bus-boat packages between Krabi and Koh Samui should take no more than three hours, though some unscrupulous private bus companies have made this a lengthy ordeal in order to rip off passengers and their stored baggage. There is a more reliable government run bus service between Krabi and Surat Thani which requires bus or tuk tuk transfer to or from the pier that services Koh Samui.