White sand
Spiaggia di Capo Comino
Siniscola, Italy · sea 25.7 °C at its warmest, in August

Sea temperature month by month
Monthly means in °C, NOAA OISST v2.1 climatology 1991–2020.
About
Beach in Sardinia
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 Spiaggia di Capo Comino?
The sea off Spiaggia di Capo Comino averages 25.7 °C at its warmest, in August, and 13.6 °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 Spiaggia di Capo Comino?
The sea reaches 20 °C or more from June to October. Twenty degrees is where most swimmers stop calling water cold; below it, a wetsuit helps.
Where is Spiaggia di Capo Comino?
Spiaggia di Capo Comino is on the coast of Siniscola, Italy, at 40.5437, 9.7975. The map on this site flies straight to it.