There are two main zones specialized for diving within Thailand, which is the Gulf of Thailand towards the east and the Andaman Sea. The climate in Thailand never disappoints the divers out there. Divers have the opportunity to discover different parts of the country for diving during different seasons. The period from November to April is the best time to Dive if you are located around the Andaman Sea and it reaches its peak again during June to September. The gulf of Thailand accommodates a highly favorable condition for divers during May to September. So basically, you could dive all year round in Thailand.