Australian architect Blecher and Danish firm Studio Fokstrot created the Copenhagen Islands project to bring "wildness and whimsy" to the capital.
Anchored to the harbour floor, the islands will be made of steel and recycled floatation elements clad in sustainable Forest Stewardship Council-approved timber.
The islands will provide a platform for relaxing, fishing or watching the stars and will be accessible by boat, kayak or swimming.
The project follows the success of a prototype artificial island called CPH-Ø1, which launched in 2018 and has hosted talks, a photography exhibition and picnics. It will soon be joined by three more islands later this year.