Hello, (I am from the UK) If I have a Spanish student visa starting on September 1st. Can I still go on holiday to other Schengen countries (like France) before it starts? Or is there some rule that you can't go to the Schengen area before?
Until such time as the ETIAS system kicks in, any UK citizen is free to visit any EU member state (for a short holiday) without any formalities other than the usual passport checks. I can't think of any reason why possessing a visa for a specific EU country should prevent you travelling to any other EU member state.