Yoshi's Island is a racing course that appears in Mario Kart 9th. It is the final course found in the Flower Cup, and is based on Yoshi's Island from Super Mario World 2: Yoshi's Island. It is a single lap course.
You start on the pink grassfields filled with Crazy Dayzees on the side. You continue and make a right turn, with item boxes, and then go through a short tunnel and find yourself in a jungle environment. On the left side you see Spear Guys at their camps, Grinders in the trees, and pass two waterfalls before entering a cave.
Inside of the cave you make an U-turn, with item boxes, and immediately exit it afterwards. You also can take the shortcut which requires a mushroom, star or any other possible boost. A single Lantern Ghost can be seen walking around on the background. The cave itself is very dark so your lights automatically go on. Once you exit the cave you suddenly go up more vertical (you already were going upwards) and thus enter anti-gravity. You drive through a waterfall and ride on the cliffside almost to the top of the mountain. You then cross a bridge, which has a tricky jump, and item boxes in the middle (don't fall off the bridge) and once you enter the next mountain you go into anti-gravity again. This time you go down and pass item boxes in the turn.
You slowly go down and pass some Toadies floating in the air, and make a left, but watch out for the crack in the ground. You then go into a lake which has a giant Lunge Fish in the core and item boxes in the second turn. After finishing the square underwater you go up shore again, cross a little stream over the path. You then drive up very high again and enter anti-gravity again as you drive sideway against the third mountain. As you exit anti-gravity you are going to make a jump to the finish with your paraglider.
The three mountains are exactly like how they originally appeared (the blue mountains). The first part, before you go through the small tunnel is set in pink grasslands with Crazy Dayzees. The second part is a jungle with Spear Guys and Grinders. The cave is pitch black with the single light of the Lantern Ghost and some Grim Leechers. The waterfalls come down from a pound from the top of the mountain. When you go down the mountains it looks similar to the sahara part although it features Toadies. The underwater part is very clear with some shells, seaweed and the Lunge Fish. When you go up the mountain again it goes into a snowy enviroment. When you make the jump you will fly with the Goonies and land on the pink grasslands again.