The best time to go diving in Thailand is November until April, particularly for liveaboards on the west coast. During this period the water is very calm and despite a few plankton blooms visibility is still around 82-92 ft. (25-30 m). Liveaboard diving outside of these times is rare with many of the best sites unreachable due to weather conditions. Whale shark season in Thailand is between February and April when these giants can be spotted cruising past the cleaning stations. This is also the perfect time to see mantas, who are following the plankton bloom.