Message in a bottle (Christmas Island)

A message in a bottle can be found in the Spirit Realm of Aminishi. The bottle is located on the beach below where the Aminishi moai rested and is revealed after talking to all four of the player's crew on each of the three main islands Waiko, Whale's Maw, and Aminishi after completion of the Jed Hunter miniquest. It can be investigated to receive a treasure map.