go to orbis using ellinia station, then to ariant from there
OR
go to manji and do his "manji and the secret group" quest. you'll get 10 free transports
to ge back, go to ariant and the portal al the way to the right, keep going that way, and eventually you'll see a guy who teleports you back to victoria island
to go from ariant to magatia or other way, go in the middle portal of either town and talk to the camel cab