There are several ways to get to Koh Phangan. Bangkok Airways operates more than twenty flights from Bangkok to Koh Samui every day. From Koh Samui you can take an express boat to Koh Phangan (around 20mins ride) Also, you can take efficient rail service or overnight sleep train down from Bangkok to Surat Thani and take a ferry from Surat Thani to the island. If you are adventurous and don't mind a long haul journey, air-conditioned bus can be one of your choices.