[spaghetti]

Blondie in facts Platamona is the edge of the "ok zone": the beach is just flat sand and a few rocks. if you like to idea of going to Castlesardo, choose a place more northeastwards: from casopetlsardo to Punta Tramontana, Marritza, Peruledda.
Otherwise, on the other direction to Valledoria and Isola Rossa: my friends say it's okay for spearing.
Anyway I got the best feedback about the zone between Castelsardo and Platamona: good spots are Punta Tramontana, Marritza, Peruledda. In this last village there is a nice resoprt called Rasciada Village hotel which has many good rocky spots for hunting that you can reach just walking. I checked the prices of the Rasciada and they seem reasonable in May.