You have to have a rainbow pass
You can't get to Four Island in Pokemon Red Version.
There is no such island in Pokémon Red.
you cant
its on cinibar island just like red blue and yellow
go to the Pokemon lab on cinnibar island
there is no mushroom island.
a valley on six island
island 4
One Island
On Cinnabar Island.
no, red
two island, but after a little while.