You don't on Island 6. You head to Island 5 and the rocket base where you will find him and the Sapphire.
1 island 6 island
you have to beat 6 gyms
you have to get a rainbow pass
you have to beat the trainers and the time in that place on seven island
Altering cave is on 5 or 6 island.
In-game Island 6 is called Fortune Island so it's possible you've already visited it in Pokemon LeafGreen. If you haven't visited it you need the Rainbow Pass from Celio on One Island. The Rainbow Pass is given if you've defeated the Elite Four and gained the National Pokedex.
Rainbow island doesn't exist.
The Ultimate Horn in Leafgreen is not an item, it's a pokemon. Heracross. You can find him on island 6 in the paddock on left from the horn house.
dont you mean wobbafett? and on 6 island down on the bottom or in cerulean cave
its in the sevii islands i think on 6 island but im not 100%sure
To open the rocket hideout, you need to get 2 codes. Lorelei will give you the 1st code in Icefall Cave. Then you go to Island 6 and go into the ruins. You will find a scientist who will tell you the 2nd code. Now go to the rocket hideout on Island 5 and beat up those miserable rockets.
To get in, use a pokemon with the hidden move CUT to get inside.hope I've helped.