The Elemental Islands are a CPC Project. It is base off the main land of Sinnoh and is like the Sevi Islands in FR/LG but it has 17 Islands, 1 for every type of Pokemon in the game! (Curse's type wasn't included because there are no Pokemon with the ??? type) To get there, you would need to have seen 400 Pokemon in your National Dex. Pokemon's levels here range from 80-100. Yes you can find and catch level00s here.
Once you have found your way to the Elemental Islands, you have to chose 3 Pokemon to be with you. Yep only 3 Pokemon are allowed to be with you. But if you catch a Pokemon on one of the Islands, you get to use it in your team. You can only have up to 3 Pokemon that where not caught in one of the Islands. You can hatch eggs in one of the islands and it will be classified as "Island Native" so you can use it for having more then 3 in your team.
Here is a pic of the Islands:
Click to enlarge
On every Island there is a Town close to the see that has a ship port. That's where you arrive. In that town it has a Pokemon Centre, PokeMart, Move Tutor, A Random Trainer Battle, 2-3 houses with People to talk to and other people outside. The Move Tutor teaches 1 move that can be done over and over again and it's based on the type of Island your on. So your on Water Island, it will be a Water attack.
There are 2 places on the islands other then the Town to go. 1 spot on the Island is a Cave that you need a key to open the main Chamber. The other is a mountain, volcano, or some other land area depending on the Island. At the end of it, there will be a trainer. He/She is the Island Leader. They have 3 level100s of that type. They may include duel types to help them.
If you win your battle with the Leader, you get a few things: Tons of cash, A plate depending on Island type (So Splash Plate for the water Island), Island Key and a TM for that type.
After you get the key for that Island, you can go back to that Cave and open the Chamber. Inside that Chamber, you will find a level100 Pokemon of that type. It could be a legend or something really bad. Every time you go to battle, it has a 1 in 8000 chance of being Shiny. It's still high but better then old chances.
