Diamond Bay, along with Willow Grove, was one of the precious few areas from Sabre's campaign from Dinosaur Planet that ended up being scrapped entirely in the final Star Fox Adventures. A massive coastal area with cascading water falls, Sabre (or Fox in the leaked Dinosaur Planet build) and Tricky would access this area by swimming down the river in SwapStone Hollow.

This was the original home of the Volcano Force Point Temple. It was also home to a single, seemingly last standing member of the PointBack tribe, a race of Stegosaurs. This individual would help Fox/Sabre by providing them the key to access the Volcano Force Point Temple, and would provide them with different tasks every time they returned from Diamond Bay with a SpellStone, such as preventing her eggs and nest from being raided by thieves, or being swept away by a flood. Completing each of these tasks would reward Sabre another key into the Force Point Temple.

It was also home to Sabre's first Krazoa shrine test, the Test of Strength. After depositing his first SpellStone, Sabre would be able to find a pathway that leads to a temple containing this shrine that was being guarded by a group of floating droids.

Diamond Bay was completely removed in the final Star Fox Adventures, and the Volcano Force Point Temple and the Test of Strength would be relocated to Moon Mountain Pass and SnowHorn Wastes respectively. Though absent in the final game, early design documents and concept art indicate that Rare did plan on bringing the PointBack back, but relocated to ThornTail Hollow (originally SwapStone Hollow).

It is worth pointing out that in the final game, there exists a mother ThornTail whose eggs and nest are similarly being raided by thieves and thus requests Fox for help. Bumping the contrast on Kevin Bayliss' early Star Fox Adventures cutscene sequence document reveals "The PointBack's eggs" on the next page, which makes it clear that this role was originally intended for the PointBack before she was dropped entirely in favor of the ThornTail.