Thailand is easily one of the most popular countries for young travelers. It’s easy to see why, with the beaches, cheap prices, and exotic culture. I found it to be too over saturated with tourism to deserve such a high reputation, but had plenty of great times nonetheless.
I visited as part of my Global Cycling Tour. The towns are remarkably relaxed compared to Myanmar. Even Bangkok was fun but not overwhelming. The islands in the south are where most travelers end up, and for good reason. Make sure to choose your island carefully - some are not worth your time.