It was TV series from the 90s about a girl who lives in a cold country, maybe US or Canada, and travels to her boyfriend in Australia through a secret gate in her room within just minutes.
There's a Irish-Australian series from 2004 about a portal and characters like you described. It's called Foreign Exchange.
Synopsis from Wikipedia:
Foreign Exchange had two major sets, one in Galway, Ireland, and the other in Perth, Western Australia. Brett Miller and his family live underneath their restaurant, only to find a rock that opens a portal into the basement level of O'Keefe's College, an Irish boarding school (which is in reality Castlehackett House, near Tuam, Co. Galway). There he unexpectedly bumps into Hannah O'Flaherty, a student from Galway, who is delighted to learn that when she turns a similar rock on her side of the portal, she can escape the grey and winter of Ireland to the sun and summer of Australia. The show revolves around these two characters, who are the only two to know and use the portal with the exception of Cormac MacNamara, who learns about the portal near the end of the season.