Paddle Boarding

I'm having difficulty finding where you are allowed to paddleboard in Spain can you just turn up on the beach or on the river? It is just I am aware of people getting fined for windsurfing on the wrong part of the beach?

I have seen them doing the stand up paddle boarding on La Mata beach and they seem to keep out from the shore to where you see the paddle boats/pedaloes and scooters. I don't know how far that marker is. I presume there is some kind of Council guidelines posted on the beaches.

Bee