"Joker's teleport only can do so much, but all the Pokemon centers in town have something that lets you teleport to the next one, if you've already been there before."

He's not sure what the point of that restriction is, but that's just how it goes.

"So as long as you're in one of the towns, I can get there."

Notably, their current location is so small it doesn't have any Pokemon centers, hence requiring even the oldtimers to get creative in getting home.