It depends on what Island you are going to visit.
The following islands are:
Dewford town: After helping the Devon corp in Rustboro city you head down and into the sailor house. Then you speak to the sailor and he will take you to Dewford.
Mossdeep city: After you you have watched team magma leave in the submarine you head out of their hideout and surf east until you find Mossdeep city.
Sootopolis city: After you have visited Mossdeep city and learned dive from Steven you can head over to the water around Sootopolis and dive. Then you look for a cave entrance and enter. Go up to the surface and you will fin yourself in Sootopolis city.
Evergrand city: After beating the gym on Sootopolis you can head east and find the path. when you get to the waterfall simply use waterfall to reach Evergrand city.
Pacifidlog town: Pacifidlog town is unlocked at the same time as Mossdeep city. You simply head south from Mossdeep and then west for Pacifidlog town.
you can find the ruby in mt ember on 1 island to the right there will be 2 team rocket members and after you beat them you go in the cave and in the end is the ruby for the sapphire go to dotted hole on 6 island
First you need to go to One island and go into the Pokemon center and talk to celio after beating the elite four and getting the national dex he will ask you to get the ruby now to get it go to mt ember which is north of one island and enter the cave that is blocked by rockets next locate the ruby now to know you found the spot to the ruby there are 2 ways to go at a certain part you go down and you will find the ruby eventually, NOTE you need a Pokemon that knows strength.
You get the ruby in one island. You have to beat the Elite 4 and have 60+ Pokemon on your Pokedex,then go to 1 island and battle the 2 team rocket guys.Then you enter in the whole on the wall and reach to the end.The ruby will be there.
After you beat the Pokemon league, go to One Island. Go to the base of Mt. Ember, where you saw the 2 Rockets. They should now be standing in front of the opening of a cave. Beat them, go in, and go to the end of the cave, where you'll find the ruby.
1.complete the leage (1st time) 2.go to 1 island 3.go to mt ember 3.collect the ruby 4.hand to celio (1 island pokemon center) 5. go 2 the ship and there you go
you get the ruby and the sapphire in 6 island and 1 island
60 Pokemon=national dex.OK go 2 1 island after beating elite4 and getting national dex go 2 moutain and talk 2 team rocket guards beat both go in get ruby talk to man with machine in PC he gives the pass 2 u go there
the red ruby is in the mountain in 1 island where 2 team rocket people are standing the blue ruby is in dotted hole
you need 2 beat the Pokemon league and have 60 Pokemon enteries on your pokedex. then you go to professor oak and he will say crap that's not important. then go talk to celio in 1 island and get the ruby at mt ember. take it back and he gives you a pass to islands 4-7.
THE RUBY IS IN ONE ISLAND(NOT FOUR ISLAND),YOU COULD GET THE RUBY AT THE TOP OF VOLCANO AND THERE WILL BE 2 TEAM ROCKET,REQUIRES YOU MUST BEAT ELITE FOUR AND HAVE NATIONAL POKEDEX,TO GET NATIONAL POKEDEX YOU JUST COLLECT 60 POKEMON(MIN) AND TALK TO PROF,OAK AND HE WILL GIVE YOU NATIONAL POKEDEX.AFTER THAT GO TO THE TOP OF VOLCANO THAT HAVE 2 TEAM ROCKET.THE CAVE HAVE OPEN BETWEEN THEM.BEAT THEM AND ENTER THE CAVE.AFTER THATYOU FOLLOW THE WAY AND IN UNDERGROUND THERE WILL BE RUBY AND TAKE IT.AFTER THAT GO TO CELIO AND HE WILL GIVE YOU RAINBOW PASS TO GET THE SAPPHIRE.
Ofcoure..But You Will Need Ruby and Saphire Stones Form Island 1 2 or 3...
beat the elite 4 and talk the guy in the one island Pokemon center and then head to mt ember and you will have to beat 2 rockets to get the ruby.