Porto: 41°9′N, 8°36′W
Invercargill: 46° 24' S, 168º 24' E
Hobart: 42° 52' S, 147° 19' E
To be perfect antipodes, they should have the same degrees of latitude, one North and the other South; and the longitudes should sum 180º.
Anyhow, that's really far far away, and it's amazing to be visited from that distance. Miracles of the Internet.
Welcome, dear 'antipodes', all the best !