From the Super Mario Wiki
Hawaii was visited in The Adventures of Super Mario Bros. 3 episode "Reign Storm". Princess Toadstool needed a break from her duty in the Mushroom Kingdom, and was ordered to go on vacation by her doctor, along with Toad.
While Princess Toadstool was in Hawaii, she met up with a surfer dude named Cutter, who quickly became her friend, and offered to give her surfing lessons. Along with surfing lessons, Princess Toadstool also went swimming, windsurfing, waterskiing and hangliding.
While Princess Toadstool was away in Hawaii, she and Toad were unaware of Bowser and Kooky Von Koopa's plan to take over the Mushroom Kingdom by using a Robot Princess in her absence. Had Toad not noticed Kooky spying on them from behind some bushes, he and Princess Toadstool would've stayed in Hawaii, allowing Bowser to successfully take over the Mushroom Kingdom.
However, Princess Toadstool and Toad knew that they had to get back right away, and left Hawaii. Although they never made any known return trips, Princess Toadstool thanked Cutter for the wonderful time she had with him, and told him that one day she'd make him feel welcome in her world. Cutter, of course, thought that she was crazy.
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