Best Time for Snorkeling in Phuket: Visibility Calendar
Visibility Overview by Month
Underwater visibility in the Andaman Sea around Phuket varies significantly throughout the year. The difference between snorkeling in peak season and monsoon season is dramatic.
| Month | Visibility | Conditions |
|---|---|---|
| January | 20-30 m | Excellent. Peak season. |
| February | 20-30 m | Excellent. Best month for most sites. |
| March | 15-25 m | Very good. Water may start warming. |
| April | 15-25 m | Good. Last month for Similans. |
| May | 10-15 m | Declining. Monsoon approaching. |
| June | 5-10 m | Reduced. Rough seas limit options. |
| July | 5-10 m | Low. Best in sheltered areas. |
| August | 5-10 m | Low. Some plankton blooms. |
| September | 5-10 m | Lowest visibility. Roughest seas. |
| October | 8-15 m | Improving. Monsoon weakening. |
| November | 15-20 m | Good and improving. Season starting. |
| December | 20-30 m | Excellent. Peak season begins. |
What Affects Visibility?
- Rainfall and runoff: Monsoon rains wash sediment into the sea, reducing clarity.
- Plankton blooms: Seasonal nutrient upwelling can cause plankton blooms that cloud the water.
- Wave action: Rough seas stir up sediment from the seafloor.
- Tides: Outgoing tides can carry murky water from mangroves and rivers.
Best Snorkeling by Destination
Similan Islands
Best months: December to April. Open only from October to May. The Similans offer the best visibility in Thailand, regularly exceeding 25 meters during peak months. Book a Similan Islands tour.
Phi Phi Islands
Best months: November to April. Shark Point and Loh Samah Bay offer good visibility year-round in calm conditions, but peak season is clearly superior. Book a Phi Phi tour.
Coral Island
Reasonable year-round. Being close to shore and in sheltered waters, Coral Island maintains decent visibility even in monsoon season. Not as spectacular as the Similans, but reliable. Book a Coral Island tour.
Koh Racha
Best months: November to April. Koh Racha (particularly Racha Yai) has good visibility and is accessible year-round on calm days.
Phang Nga Bay
Visibility in Phang Nga Bay is generally lower than open ocean sites because of the mangrove sediment. This is a kayaking and sightseeing destination, not primarily a snorkeling destination. Book a Phang Nga Bay tour.
Tips for Best Snorkeling Visibility
- Visit December to March for the clearest water at all sites.
- Go early in the morning. Water is often clearest before afternoon winds and currents stir things up.
- Choose offshore islands. Similan, Surin, and Phi Phi have better visibility than sites close to shore.
- Avoid snorkeling right after heavy rain. Runoff reduces visibility, sometimes for 1 to 2 days.
- Bring a good mask. A properly fitting mask with anti-fog treatment makes a big difference. Tour-provided masks are often basic.
For the best snorkeling experience, plan your trip during the peak visibility months and choose offshore destinations. Browse our available tours for snorkeling-focused options.
