Mount Hokulani (Japanese: ホクラニ岳Mount Hōkūlani) is the second-tallest mountain in Alola, located on Ula'ula Island. The Exeggutor Express takes passengers from the mountain's base on Route 10 to the summit, where the Hokulani Observatory is located.
In the anime, Mount Hokulani is home to Starfall Hill, which is known for the large amount of Minior that fall there. There is also a cave that runs beneath it and Mount Lanakila that serves as a shortcut to the port.
Later, after the Ultra Beasts were done destroying Malie City and started to move on, Professor Kukui, Sophocles, Molayne, Acerola, and Gladion fought a Celesteela and a Guzzlord at the Mount Hokulani mountainside. Thanks to Gladion and his Type: Null, the Ultra Beasts were defeated before they could reach the observatory; in the process, Type: Null evolved into Silvally while saving Lillie from Guzzlord. Gladion and Lillie were glad to meet each other again, while Professor Kukui, Professor Burnet, and Acerola were shocked to learn that they were siblings. Lillie then told Gladion about how Nebby had fallen asleep and showed him a flute that she had taken with her while running away from Aether Paradise. Upon seeing the flute, Gladion urged Lillie to go to the Altar with him.