Tmesis

The Tmesis is a man-made structure that you visit inbetween K Island and H Island.

Locations:

Tmesis (The main location in the Tmesis.)

Team PokaPoka Warehouse (Another Team PokaPoka base. The second place where you fight against Pnf, the leader of Team PokaPoka.)

Tmesis Gym (The 7th gym. It is only available after clearing the Team PokaPoka Warehouse.)

Tmesis Port (Where you take a boat to H Island once you're finished with the Tmesis. It is only available after you beat the Gym and Team PokaPoka Warehouse.)

Also see M Island, J Island, K Island, H Island, and Cyberspace.