How do you catch to the seventh island in Pokemon firered?
First goto One island. get the ruby (or sapphire i think) and bring it to Celio (bill's pokenerd friend) he will give you a rainbow pass. you can now access islands 1 - 7. but you gotta have beat elite four and have national pokedex
Beat the Elite four. Make sure you Owned 60 Pokemon in pokedex. Go to professor oak. He will give you the National PokeDex.
Sorry I'm not singed in but this is Kyogre286 writing.
So after you beat the seventh gym Bill will ask you to go on a cruise. You can say yes or no. If you say no go to Viridian and battle Giovanni. If you say yes go teach your starter Pokemon a move on two island or three island. After that go to three island and catch Moltres. [This is what I did on Pokemon firered! It might not be correct.]
Catch Electabuzz (can only catch in FireRed- not LeafGreen), and go to four island (have to have beaten elite four and gotten 60 Pokemon in pokedex to go to four island). Leave Electabuzz and some other Pokemon (preferably Ditto) in the daycare, come back after a while, get the egg from the man, and it will hatch into an Elekid.