Doubtful Sound contains challenges for Pacific Run.
Doubtful sound contains an underwater docking station where Nancy can take a submarine underwater and look for items for a challenge.
In the docking station, there is a large turtle display that Nancy has a to complete a puzzle with, a puzzle specifically for her. There is also a puzzle to fuel the submarine and a puzzle involving the submarine.
Doubtful Sound also has a kayak race where Nancy must beat other competitors times racing in the kayak of her choice to touch colored buoys in a certain order.
Away from the dock, there is a path that leads to a tree. Here, Nancy eventually finds a stolen medallion piece and almost gets hit by a rock.