The 2020 lineup will be announced closer to the festival.
Thong Nai Pan
Koh Phangan, Thailand
There is a boat that goes directly to Thong Nai Pan from Samui. It only leaves once a day at 12pm and takes 2 hours (it stops at all beaches along the East coast).
If you can't make that one there are 4 other options. Lomprayah and Seatran which go to Thong Sala, Haad Rin Queen which goes to Haad Rin, and the speedboat which goes to Baan Thai.