Can you also say: Je vis dans Perth

"Je vis à Perth" would be the correct way. -- Chris (not a native speaker).

Bonjour Lesley ! "Je vis dans Perth" would mean something different as it insists on the fact that you live inside the city, in the center of it, as opposed to in its suburbs, or just outside of it. And even then, you'd rather use "J'habite dans Perth.". Bonne journée !

Merci !