One Island

Bill gives you the Meteorite in the Network Center when you first arrive, to carry to the Joyful Game Corner on Two Island.

Celio hands over the Rainbow Pass beside the Network Machine, 6 tiles east and 3 north of the door, after you bring him the Ruby.

Celio gives you a Town Map in the Network Center when you first arrive, but only if you did not already get one in Pallet Town.

Celio gives you the Tri-Pass in the Network Center when you first arrive, covering ferries between One, Two and Three Island.