Pikachu no Kaiyou Adventure

ピカチュウの海洋アドベンチャー

When Pikachu and friends decide to stop by a tropical island for some rest and relaxation, they got more than they had bargained for after Chatot discovers a Treasure Map! They follow the map to Wailord’s Tear, a mysterious place located in a sunken pirate ship. Will Pikachu and friends find the treasure? What mysteries and dangers are in store? Will our pals return safely? Find out in Pikachu’s Ocean Adventure!

(Source: Bulbapedia)