If you’re an avid sailor, keen to test your skills, or just someone who likes to watch competition sailing, then here’s a web site you need to know about: Regatta Thailand list all of the up-coming regattas, along with the dates they will next be held, rules, and other useful information. As they point out, "regattas in Thailand are all exceptionally well organized events. They usually consist of four to five days racing with sometimes a lay day in between. There are even more early night parties serving food and entertainment on different exclusive beach and resort venues."
Regatta Thailand is a product of Andaman Sea Club sail charters. They have several boats for charter, including a Firefly 850, "Asia’s hottest racing one design class". I’ll probably be talking about them some more at some point in the future.