Mainau also referred to as Mavno, Maienowe, Maienow, Maienau, Mainowe and Mainaw is an island in Lake Constance. It is maintained as a garden island and a model of excellent environmental practices. Administratively, the island has been a part of Konstanz since December 1, 1971, when the municipality of Litzelstetten, of which Mainau was part, was incorporated into Konstanz. Mainau is still part of Litzelstetten, now one of 15 wards of Konstanz.
The island belongs to the Lennart Bernadotte-Stiftung, an entity created by Prince Lennart Bernadotte, Count of Wisborg, originally a Prince of Sweden and Duke of Småland. It is one of the main tourist attractions of Lake Constance. Beside flowers there is a park landscape with views on the lake. There is a greenhouse as well with tropical climate and thousands of butterflies.
Mainau Bay is the location of their university's sailing club.