Haad Rin is situated on the south east of Koh Phangan. There are 2 parts: Haad Rin Nai and Haad Rin Nok, curved into 2 shapes for length 2 kms.
Haad Rin Nok (sunrise)
Haad Rin Nok is the fullmoon party beach on the sunrise side of the cape. Here is good for sunbathing during the day and full of night life during the night.  Food and drink here seem to be pretty higher than other beachs.
Haad Rin Nai (sunset)
Haad Rin Nai is the west side, fullfilled with several high-end resorts, more private.  The beach is usually fairly deserted with the length of 1 km, suitable for sun bathing.  Haad Rin Nai is near pier to the pier: Big Buddha of Koh Samui, usually 4 trips a day.