This glowing effect in the water at night is a phenomenon that occurs all over the world, but especially in warm water areas. In Florida, we had it around Clearwater, and Tampa as I fished at night from bridges. When We dragged bait through the water, or when fast fish like mahi-mahi ripped through the water they left eery blue-green s-shaped curvy trails.
Here in Krabi there are a number of places you can go to see the plankton. Ideally, you’ll be in an area away from the mainland where the water is clear and there have been no storms for a few days. The water should be calm and clear for the best effect.
Where Is the Best Place in Krabi to See the Water Glow Blue?
You can come to Krabi, Thailand and see this glowing plankton for yourself! Yes, you have to be a bit lucky as it doesn’t happen every night. Pay attention to the following tips and you’ll have the best chance of experiencing this once in a lifetime experience of swimming in or just walking through bioluminescent plankton in a blue-green blur!
One of the best places in Krabi to see bioluminescent plankton in Krabi, Thailand is at Railay Beach West. The west side of Railay has some areas of caves by Phra Nang cave and this is a good spot to see the glowing plankton. Another option is taking a night boat tour that includes a stop at Ko Hong, Ko Poda, or one of the other islands close to Railay or Ko Phi Phi where you have a good chance of seeing this glow.
Remember, there is not 100% chance you’ll see this amazing effect. There are some factors that affect your ability to see it. Time of year. Time of night. Phase of moon. Water temperature. Currents. Clarity of water. All of these affect your chances.
What time of year can you see bioluminescent plankton in Thailand?

Coming to Railay Beach, Krabi during the high season (November to April) can increase your chances of seeing the plankton. Going on a clear, moonless night is highly recommended.
The bioluminescent plankton are easier to see during the time just before, during, and just after the start of the new moon because it’s darkest. So, the best times of 2023 will be during November and December of 2023, but really anytime around a new moon can produce the awesome result you’re looking for!
New Moon Dates for 2023
Come 1-2 days before, during, or 1-2 days after the new moon phase and you will have the best chances of seeing the plankton glowing blue in the water around you.
- January 21, 2023 (come 19-23rd)
- February 20, 2023 (come 18-22nd)
- March 21, 2023 (come 19-23rd)
- April 20, 2023 (come 18-22nd)
- May 19, 2023 (come 17-21st)
- June 18, 2023 (come 16-20th)
- July 17, 2023 (come 15-19th)
- August 16, 2023 (come 14-18th)
- September 14, 2023 (come 12-16th)
- October 14, 2023 (come 12-16th)
- November 13, 2023 (come 11-15th)
- December 12, 2023 (come 10-14th)
Does rain help or hurt your chances of seeing the glowing plankton?
Rain can cloud the water and hurt your chances of seeing the bioluminescence very clearly. When there is more dirt in the water it can hinder your view of the glowing plankton. It’s best to go in water that is very clear and undisturbed by streams and rivers flowing into the ocean.
How do I take photos of bioluminescence with my phone?
Start taking photos of the bioluminescence by using a high ISO setting like 400 or 800, even higher if you can. Choose a wide aperture of f/2.8, 2.0, 1.8 (or as low as you can go) to allow as much glowing light to come through and hit the sensor as possible. Try photos and videos.
You can move your hands through the water to trigger the glows. You can also take photos while waves are coming in and hitting you or someone standing in the water for the best effect.
What is bioluminescent plankton?
Bioluminescent plankton (bioluminescent phytoplankton), are microorganisms that can emit light through a chemical reaction within their cells as a response to a threat, like hitting something in the water, or something moving through the water. These tiny organisms are found in both freshwater and marine environments.
Photopores inside the plankton create a chemical reaction that combines with oxygen to produce the eery blue-green glowing light we see with these plankton in the sea. Luciferin, oxygen, and luciferase all combine to create the glowing effect.
Bioluminescent plankton cause a blurry light to be seen in the water at the beaches in Krabi at night during dark nights. When these plankton are disturbed by movement in the water, evena breaking wave, they emit a sparkling display of light that looks surreal for people close by or in the water.
Other areas of the world that have these magical displays include Puerto Rico, Hawaii, the Maldives, and Florida (plus many more!).