Beach
Anse Possession
Seychelles · sea 29.9 °C at its warmest, in April

Sea temperature month by month
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020, sampled 13 km offshore, at the nearest open water cell of a 0.25° grid.
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 Anse Possession?
The sea off Anse Possession averages 29.9 °C at its warmest, in April, and 26.3 °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 Anse Possession?
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 Anse Possession?
Anse Possession is on the coast of Seychelles, at -4.3119, 55.7285. The map on this site flies straight to it.