Mokoia Island in the middle of the lake is small but significant. The island is owned and governed by four local hapu (tribes) of Ngati Whakaue, Ngati Uenukukopako, Ngati Rangiwewehi and Ngati Rangiteaorere. Mokoia Island is very sacred to the local Maori people and holds a prominent place in Maori cultural history.

This is the location of one of New Zealand's most famous love stories, that of Hinemoa and Tutanekai. According to legend, the two lovers were forbidden to marry, and Hinemoa's father Umukaria, a chief from the shores of the lake, ordered that she not be allowed to travel by canoe to Tutanekai's village on the island.

Hinemoa decided to swim across the lake to the island, guided only by the sound of Tutanekai's flute-playing. Guided by the melody of the flute, Hinemoa swam through the dark waters until she reached Mokoia Island. She staggered exhausted up the beach and into the comfort of a natural hot pool.

Unlike many others, this story has a happy ending and still lives on today, with murals and statues to depict the scene, with Hinemoa Point where the swim began, and Hinemoa's Pool where it ended still to be seen.

Mokoia Island is also an important conservation reserve. A number of endangered species have been introduced to the island, including the Weka, North Island Robin (Toutouwai), and Saddleback (Tieke). You may also see native birds such as the Pukeko (swamp hen), Papango (Teal), and the famous Tui. Kiwi birds also live on Mokoia Island, but they are active only at night.