What kind of guitar? Acoustic/classical, electric...?
Electric is probably fine if you play with headphones rather than an amp.
Acoustic/classical I imagine your flatmates may be less keen on and it might be pragmatic to seek out a music practice room on campus instead. If you only play e.g. in the middle of the day or something though and just for short-er periods a couple times a week at most this might be less of an issue. If you practice every day for over an hour this might be an issue for them though, especially if you principally do so in the evenings.
Obviously in any event I'd suggest avoiding doing it between 9pm and 9am.