Koh Lipe is a very small island in the Andaman Sea. Going there from Bangkok is not so easy. You must first fly to Hat Yai or Trang. Then count two hours by taxi or bus to the pier to finish with two hours of fast boat.
The island is really not big. You can go from North to South in a few tens of minutes. Speedboats arrive on Pattaya Beach, from where the walking Street ("pedestrian" street) starts, which is one of the 2 shopping streets.
Walking Street
Although there are a few nice restaurants and bungalows on this beach, Pattaya Beach is the least friendly beach on the island, among other things because the regular boat traffic that brings tourists pollutes a lot.
Pattaya Beach
On the other side of the island, there are absolutely incredible beaches.