I was in Puerto de la Cruz today, and decided to go for a swim in the sea. It was just east of the swimming pool complex on a black sand beach, where a few surfers were.
The sea was quite rough (although partially protected by a sea wall), and I didn't notice the red flag, as I approached it from the side. Without appearing immodest, I'm a very strong swimmer, having swim over 6 miles in a rough sea previously, and I'm swimming a 9 mile sea swim later this year. I wasn't in any danger as far as I'm concerned, although I would say it was dangerous for a less competent swimmer.
Anyhow, after 10 minutes swimming, a lifeguard blew his whistle and ordered me to get out. I politely asked him why, and he turned his back on me. After I got changed I tried asking again, and he just pointed to the police behind, as if that explained it!
So my question is, is it actually illegal in Spain to swim in the sea when there is a red flag? Do lifeguards have the authority to order people out of the sea? I always assumed that flags were an indication of the risk, and it was up to the individual to decide.
Thanks for any clarification.