The famous full moon parties are held in Koh Phangan, a little island, 45 minutes big boat ride from Koh Samui. Some people do not want to stay at Koh Phangan for the full moon party for various reasons. The common ones being the increased number of break ins into people’s rooms during the night of the party, the fact that most hotels will force you to stay for at least 3 nights and of course the higher hotel prices.
So if looking for an alternative island to stay on, Koh Samui is the perfect place to stay at (I’ve done it). So on the day of the party, there’s 2 ways you can get from Koh Samui to Koh Phangan.
Take a local taxi for about 50 – 100 baht to Big Buddha pier.
Then either buy the boat ticket to Haadrin, Koh Phangan at the pier or pre buy from one of the many agents all over the island for 200 baht one way.
The last boat leaves at 6:30 pm.
You walk from Haadrin pier at Koh Phangan to the beach where the party is held, so no transport needed there. Just follow the crowds and the noisier it gets, the closer you are. The first boat leaves at 9:30 am the next morning. So you will have to be up till then. This way you will spend about 500 baht on transport
Buying a tour
Alternatively, you can buy an all round trip for 1000 baht, (negotiate it down to 800 baht). The fare includes pick up from your hotel to the pier, then transfer to Koh Phangan by speed boat and transfer back to Koh Samui and drop off at your hotel. The advantage with buying the package is that you will be picked up and dropped off at your hotel, you can leave as later as 10 pm and you can return whenever you want. There’s speed boats running between Koh Phangan and Koh Samui hourly so you don’t have to stay up till 9:30 am. However, I’ve heard that the speed boats can be very crowded and are sometimes unsafe since they drive at night on sometimes unstable waters.