Jansom Bay - Koh Tao
Jansom Bay is one of our quiet favourites on Koh Tao, perfect if you’re looking for a relaxed afternoon dive away from the usual crowds. It’s got a lovely, sheltered feel to it, often much calmer than some of the more exposed sites. We’ve had some cracking dives here just drifting along the sandy bottom, spotting an impressive number of bluefish and golden trevally cruising past. The real joy of Jansom Bay is how much you can just slow down and observe. We’ve spent ages watching iridescent blue trim and green-blotched parrotfish meticulously grazing the corals, their jaws clicking softly in the current. Look closely amongst the rocks and you’ll often find miry’s demoiselles zipping about and sometimes a grumpy-looking rock cod peeking out. It’s not a site for big pelagics, but for a tranquil dive where you can really soak in the smaller details and the gentle sway of the water, it’s a winner. We usually head here mid-afternoon, when the light hits the bay just right, illuminating the sand and attracting the pink anemonefish in their homes. It suits divers who prefer a leisurely pace and enjoy patient macro spotting over zooming around deeper reefs.
- Location
- Koh Tao, Thailand, Southeast Asia
- Coordinates
- 10.080216, 99.816990
- Type
- reef
Marine Protected Area: Suratthani Environmental Protected Area
Best Time to Dive in Koh Tao
The warmest water temperatures in Koh Tao occur in May, averaging 30.6°C. The coolest conditions are in January at 28.3°C.
Monthly Water Temperatures
- January: 28.3°C
- February: 28.6°C
- March: 29.3°C
- April: 30.2°C
- May: 30.6°C
- June: 30.2°C
- July: 30.0°C
- August: 29.7°C
- September: 29.4°C
- October: 29.2°C
- November: 29.3°C
- December: 28.6°C
Nearby Dive Sites in Koh Tao
Nearest Dive Centres to Jansom Bay
Marine Life in Koh Tao
Home to 56 recorded species including 35 reef fish, 11 sharks & rays, 4 other, 2 hard corals, 1 clams & mussels, 1 sea urchins.
Notable Species
- Stony coral (Porites lutea) - Hard Corals
- Jack (Selar crumenophthalmus) - Reef Fish
- Largescaled Terapon (Terapon theraps) - Reef Fish
- Butterfish (Scatophagus argus) - Reef Fish
- Flying Gurnard (Dactyloptena gilberti) - Reef Fish
- Lattice monocle bream (Scolopsis taenioptera) - Reef Fish
- Blackedged Blaasop (Arothron immaculatus) - Reef Fish
- Star Blaasop (Arothron stellatus) - Reef Fish
- Fluted clam (Tridacna squamosa) - Clams & Mussels
- Short Mackerel (Rastrelliger brachysoma) - Reef Fish
- Six-banded Rock Cod (Epinephelus sexfasciatus) - Reef Fish
- Congaturi Halfbeak (Hyporhamphus limbatus) - Reef Fish
- Comb goby (Paratrypauchen microcephalus) - Reef Fish
- Long-spined sea urchin (Diadema setosum) - Sea Urchins
- Pacific blue swimming crab (Portunus pelagicus) - Crabs & Lobsters
- sea grapes (Caulerpa lentillifera) - Seagrass & Algae
- Slender Hammerhead (Eusphyra blochii) - Sharks & Rays
- Horseshoe Crab (Tachypleus gigas)
- Bluespotted stingray (Neotrygon kuhlii) - Sharks & Rays
- Deep Body Silver Biddy (Gerres erythrourus) - Reef Fish
Recommended Packing List for Jansom Bay
Based on average water temperature of 29.5°C, currents 14 cm/s.
- Shorty or Rashguard - warm 29°C water needs minimal exposure protection
- Mask - essential for every dive
- Fins
- BCD - buoyancy compensator
- Regulator - your most safety-critical piece of gear
- Dive Computer - tracks depth, time, and NDL
- Surface Marker Buoy (SMB) - essential for boat pickups
- Dive Torch - useful for crevices and colour at depth
- Underwater Camera - capture your diving memories