Yes, you can definitely bring your phone. Your phone can also be useful for taking photos, for example. The important thing is to check with your operator what type of subscription you have so you know how much it costs to call and surf from the destination you are going to. Some accommodation includes wifi and some does not. However, you will not be allowed to use your phone in class or on certain activities you take part in. In the evenings, it’s simply much more fun if you’re with your new friends on the trip instead of keeping in touch with your friends at home.