Beach
Ba Kantiang Beach
Ko Lanta Yai, Thailand · sea 30.3 °C at its warmest, in May

Sea temperature month by month
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020, sampled 15 km offshore, at the nearest open water cell of a 0.25° grid.
About
beach on Ko Lanta, Thailand
Wikipedia has no article about this beach yet. It is on the atlas from its Wikidata record and its photograph.
Questions
How warm is the sea at Ba Kantiang Beach?
The sea off Ba Kantiang Beach averages 30.3 °C at its warmest, in May, and 28.5 °C at its coolest. These are monthly means from NOAA's OISST v2.1 satellite and buoy record for 1991 to 2020, sampled at the beach's own coordinates.
When can you swim at Ba Kantiang Beach?
The sea reaches 20 °C or more from All year. Twenty degrees is where most swimmers stop calling water cold; below it, a wetsuit helps.
Where is Ba Kantiang Beach?
Ba Kantiang Beach is on the coast of Ko Lanta Yai, Thailand, at 7.4962, 99.0742. The map on this site flies straight to it.