Best nights to see Koh Rong's glowing plankton this season: new moons on 10 October, 9 November and 9 December

The dry season on Koh Rong begins in November, and with it the best time for one of the island's main attractions: bioluminescent plankton. The glow comes from microscopic dinoflagellates that light up when the water moves, and it is easiest to see on the darkest nights. This season the new moons fall on 10 October, 9 November and 9 December 2026 (Cambodian time), so the few nights around these dates are ideal. Go after about 7 pm and away from resort lights: evening boat tours from Koh Touch (typically $20-30) end with a swim in a dark bay, and at remote Lonely Beach the glow can often be seen right from the shore. Never swim alone at night. More in our new guide: Bioluminescent plankton on Koh Rong.