Finding the state of beaches - a useful link
It's summer and one of our common challenges is choosing which beach to go to for swimming (it's a hard life I know), particularly when there's a little bit of wind or the possibility of waves. Depending on the direction the beach is facing the sea can be like a millpond in one place and almost perfect for surfing some where around the coast. From where we are, just a little inland, it can be impossible to tell what the sea will be for swimming.
We have added webcams to give a little bit of a view, but I've just discovered that Gencat (the Generalitat or provincial government), keeps track of the state of the beaches and water - including whether stinging jellyfish have been seen.
https://interior.gencat.cat/ca/arees_dactuacio/proteccio_civil/estatplatges/
Our general practice is to start with beaches with shallower bays earlier in the season like La Fosca, then slowly move towards deeper water bays as the sea temperature increases since the water stays clearer and cooler.
And if you're new to the Costa Brava, it's worth pointing out that the town beaches, some of which can be a bit gritty and steeply shelving, often have neighbouring calas where the sand is finer, where there are more rocky areas for observing fish and that feel more like the classic holiday beaches.