Matlang Island
Matlang Island is a dive site in Koh Samui, Thailand. The sea floor at the site position lies at about 11 meters. Currents typically run at 0.9 km/h and reach 1.8 km/h on the strongest days. Water temperatures range from 29°C in December to 32°C in May. The typical daily tidal range is about 1.2 m. Species recorded in the area include Dorippoides facchino, Doublebar Rabbitfish, Longfin Bannerfish, Staghorn Damsel and Scissortail Sergeant.
Dive Conditions
Data sources: currents and water temperature from Open-Meteo Marine (CC BY 4.0), hourly model values 2024; seabed depth from the GEBCO 2020 Grid, sampled at the site coordinates (grid resolution about 450 m). Tidal range is the median daily range of modelled sea level from Open-Meteo Marine, hourly values 2024. Species observations from iNaturalist, checked against the World Register of Marine Species.
Conditions at Matlang Island through the year
Sea surface temperature at the site coordinates, averaged per month from hourly model values for 2024. The water is warmest in May at about 32 °C and coolest in December at about 29 °C, a spread of 3.5 degrees across the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 28.6 | 29.0 | 29.6 | 31.6 | 32.0 | 30.7 | 30.3 | 30.6 | 29.9 | 30.4 | 29.6 | 28.5 |
Ocean current at the site runs at a typical 0.9 km/h. In the strongest tenth of the hours modelled for 2024 it reaches 1.8 km/h, which is when entries are normally timed to slack water at the turn of the tide.
The tide moves the water level by a median 1.2 m over a day, and by up to 1.6 m on the largest days of the month. That range drives how much water is exchanged over the reef and when the current turns.
In the open sea off Matlang Island, the highest wave of the day exceeded 1.5 m on 0.2 % of days between 2015 and 2024. The roughest month was January (1 % of days), the calmest March (0 %).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
The seabed directly under the site coordinates sits at about 11 m. This is a bathymetry grid value with a cell size of roughly 450 m, so it describes the depth of the area rather than the deepest point a dive can reach.
Satellite habitat mapping places Matlang Island on a back reef slope, over a seabed mapped as sand.
How Matlang Island compares
These comparisons use only the measured values above, set against the 376 dive sites published on findadive.com. A percentage shows the share of other sites with a lower (or higher) value, so it reads the same way wherever the site is. Matlang Island sits with its mean water temperature in the top tenth and its tidal range in the bottom tenth of all listed sites.
| Measure | This site | Compared with all sites | Median in Thailand |
|---|---|---|---|
| Mean water temperature | 30.1 °C | warmer than 98 % of the other 375 sites | 29.7 °C (126 sites) |
| Water temperature in the coolest month | 28.5 °C | warmer than 67 % of the other 375 sites | 28.7 °C (126 sites) |
| Typical current | 0.9 km/h | weaker than 62 % of the other 375 sites | 0.7 km/h (126 sites) |
| Current in the strongest 10 % of hours | 1.8 km/h | weaker than 63 % of the other 375 sites | 1.3 km/h (126 sites) |
| Median daily tidal range | 1.2 m | smaller than 90 % of the other 375 sites | 1.6 m (126 sites) |
Water temperature, current and tide from Open-Meteo Marine (CC BY 4.0), hourly model values for 2024 at 9.5974°, 100.0657°. Seabed depth from the GEBCO 2020 Grid. Wave statistics from ERA5-Ocean via Open-Meteo Marine (contains modified Copernicus Climate Change Service information 2015–2024), daily maximum wave height on a 0.5° grid; land shelter tested against Natural Earth coastlines. Reef structure and seabed cover from the Allen Coral Atlas © 2018–2023 Allen Coral Atlas Partnership and Arizona State University (CC BY 4.0).
Marine life recorded at this site
Research-grade observations from iNaturalist within about 12 km of these coordinates.
