Although lockers are becoming more and more common in hostels, some hostels do not have this service and you will have to take extreme precautions.
As a general rule, the level of crime on the Camino de Santiago is very low and all pilgrims share the same values of solidarity and respect for others. But since there are bad people in everyone, you will have to apply logic and common sense.
If you want to avoid unpleasantness try not to leave money or valuables in sight. We recommend using a fanny pack or small backpack to keep your belongings with you at all times and placing a small padlock on your luggage.