It lies immediately north of the much larger Matiu/Somes Island, from which it is separated by a channel about 50 metres (55 yd) wide.

The name Mokopuna Island was restored in August 1947 after a request from the Wellington Beautifying Society to the Geographic Board of the Lands and Survey Department.

[3] In November 1947 a member of the public reported that rabbits were numerous on Mokopuna Island, having been let loose there by an unknown person.

The transfer of ownership was part of cultural redress for Taranaki Whānui included in the settlement of their claims against the Crown for breaches of the Treaty of Waitangi.

[6][7] A kaitiaki (management) plan was prepared in 2012, to guide the administration of the island in accordance with the Reserves Act 1977.