The Full Moon Party is actually on Ko Pha Ngan, but if you're staying on Koh Samui you can either book a ticket for the ferry there and back, or just turn up at the docks on the evening and there are several boats going there and back. Many hostels, and sometimes touts in the streets offer tickets in advance, so if you can it may be a safer bet to do so. Just be cautious of the touts, if in doubt don't buy from them.
I did consider staying on Ko Pha Ngan, which is a beautiful island, possibly more so than Koh Samui. However the problem is that during the Full Moon Party the prices of hotels sky rocket, and many hotels state that you must stay on the island for several days. As it was fairly easy to get a boat across and back, I decided to make Koh Samui my base and still visit Ko Pha Ngan for the full moon party.
The Full Moon party was epic! I loved it! Helayna and myself didn't actually arrive until it was getting dark, which I think worked out well. If you arrive too early then you may not last the night. There is a lot of heavy drinking and partying, so try to pace yourself if you want to last.
It's possible to buy drinks at the bars, but these can be a little expensive. They also sell buckets of drink. When I say "buckets", they are just that, buckets! Usually filled with a spirit and soft drink, although there are claims that these are sometimes spiked with drugs.
If you really want to save money then I suggest visiting the 7-Eleven which you'll see as you enter the party. There's often a queue, but be patient and you cans stock up on cheap drink. I bought my own bucket, spirit and soft drink, which lasted me a while. I then just topped it up or bought bottles of beer from other 7-Elevens as the night went on, it works out much much cheaper.
On the subject of drugs, be very careful. Do not bring drugs to the Full Moon Party! If you are caught with them then you'll have to pay a very hefty fine if you're not arrested.
You may have locals offering to sell you drugs on the island. Whatever you do, don't agree or even seem interested. Most likely than not these will be police officers or locals who then inform the police to earn a percentage of the fine you'll be forced to pay.
There are many locals offering to paint your face or body with fluorescent paint. Their art work is usually very good, however during the evening this will easily rub off, and it can be quite expensive when having a local paint it on. We opted for buying our own paint and brushes from a local shop and painted ourselves with simple designs. I would recommend wearing some form of body paint as it looks great once you get under the UV lights and adds to the fun.
There are various bars which run along the beach front, all playing different types of music, so you can find a bar that suits your taste. All of these bars seem to be lively and full of revellers enjoying themselves. If it gets a bit too loud or crazy then there are plenty of areas of the beach you can chill out at.
Also along the beach and in the bars you'll find various games happening, usually involving fire. There will be slippery slides which pass through rings of fire and fire limbo! But perhaps one of the most popular games is the fire jump rope. A hope rope of fire is looped up and down for party goers to jump over. Some people are great at this, and it's very impressive to watch. However if one party goer gets hit, the chances are the others will too.
You can actually receive quite serious burns if you're not careful. I suggest getting into the water quick if you are burnt! Certainly think twice about taking part, especially if you're drunk and your reflexes may not be so sharp.
On the subject of the water, it may be best to be avoided. There are many toilets by the bars, but you have to pay to use these toilets and there can often be long queues. Therefore many people, male and female, take to the sea instead.
As far as I'm aware they only urinate in the sea, hopefully they don't poo. I will hold my hand up and also admit to walking into the see to pee, as the long lines for the toilets simply weren't a reasonable option. I'm not saying I suggest using the sea as a toilet, as you'll basically be wadding into a mixture of water and other peoples urine. But if there is a huge line for the toilets, and I mean huge! The sea may be your only option.
There are places on the beach reserved for severely drunken people. So if yourself or a friend is in quite a bad way, you can drop them or yourself off there to sober up a bit.
However as the night goes on you'll eventually start to find several bodies scattered along the beach. At first glance it may feel like you're in a war zone avoiding dead bodies, but as far as I'm aware I was only stepping over passed out people.
I am happy to say that although Helayna went home before me, I made it until sunrise.
During the night I met several interesting people from all walks of life, including a friend I had previously met in Helsinki.
There was much dancing and partying, and it was one of the best parties I've ever been to. This is my main pull to go back to Thailand.
If you can I would recommend planning your trip around the full moon. You'll be able to find a calendar online. If you don't visit during full moon, there is also a Half Moon Party which I believe happens in the jungle. Whereas this is not as popular, I think it could still be a great night.
The only downside to the Full Moon Party was the following day. I don't often suffer from hangovers, but I was in quite a bad way. I wasn't up and functioning until late afternoon, and I was not able to drink much the following evening.