Cobalt Island serves as the main setting for "The Treasure Hunt" activities. Here, bananas and coconuts can be collected. However, in order to unlock Cobalt Island, the player and Pikachu must have broken open the pinata three times during "The Piñata Party" event. After doing so, a Lapras will agree to take them to Cobalt Island where many treasures lurk.
Cobalt Island is basically a small island that contains many treasures buried underground. The player must tell Pikachu to dig one up when they are near one. Afterwards, the treasure chest can be opened with a certain command such as Thunderbolt or Thunder. The treasure chest will then open and Pikachu will give then give the prize to the player. It should be noted that, during Part 2, there is a large cannon at the top of a cliff. Making the cannon go off will cause all of the other treasures to come up to the surface making opening them quicker before sunset. This is also where you can gather bananas, spiny shells and coconuts.