You’re unlikely to encounter any violent crime in Granada, however personal theft is a known issue. Pickpockets usually operate in crowded areas so be careful of people who bump in to you- they might be distracting you from your wallet. Keep your valuables securely on you, no, back pockets do not count!
Take extra care, especially during festivals and evening entertainment, on crowded buses and trains. Also, beware of hanging your jacket over a chair in restaurants and cafes. Don’t make your stuff easy to grab. Keeping everything close and in your eyeline is your best bet.