Star Island (B1 on the map) is one of the 49 different islands featured in The Legend of Zelda: The Wind Waker for the GameCube. Like most of the islands in the game it's very minor and only features a few sidequests. One of the sidequests can only be done by completing the Forbidden Woods. After doing so Oakin, one of the Korok creatures, will be here to start new forests.
There's a Sea Platform way out in the ocean that contains nothing noteworthy at the top. On the island you can find a Blue ChuChu and a Piece of Heart by blowing up a rock that will lead the character to a bunch of enemies. After they're all killed you'll be given access to the Piece of Heart. Finally by using Treasure Chart #7 you can nab yourself a Silver Rupee.