On the Sea Chart, Hidden Island 1 appear as a barren rock. In truth, it is a lush tropical isle with fertile brown soil, grassy cliffs and palm trees. In the background, a view of the sea with small tropical islands and white clouds in the horizon can be seen.
Hidden Island 1 is located to the far west from Machine Labyrinth, just west of Coral Cave; however, Coral Cave will not appear until after the player clears Hidden Island 1.
After arriving on Hidden Island 1, Sonic, Tails and Marine found an ancient statue. Curious as ever, Marine touched it despite her friends warnings, causing the ground to shake and reveal Coral Cave, the trio's next destination, as it resurfaced in the water.
Like most other Hidden Islands, Hidden Island 1 is a short stage which can be finished in less than a minute. Here, the player mainly has to scale several steps and platforms to reach the Goal. What makes this tricky is that barrel-throwing Badniks and Pirate Hogans are placed at all the ledges and ascending spots: if the player ascends in these spots carelessly, they will move straight into the enemies' attacks with no means of protection.
At the beginning, the player has to cross several low steps. At the end of the path, the player arrives at a series of enclosed platform levels located above which must be scaled vertically using Springs on each platform. At on top, the player only has to scale a few more low steps before arriving at the Treasure Chest.
Hidden Island 1 is the first of the Hidden Islands that the player plays through as part of the story.