A 120-room floating hotel could be moored in Cardiff Bay by 2027 under a proposal by developers.
Plans have been revealed by Finnish company Meyer Floating Solutions and the UK's Morfield Floating Hotels for the boutique hotel on a dedicated berth in Roath Basin near the city's landmark Norwegian Church.
A 15,000-seat arena being built in Cardiff Bay means there is "room for another hotel", said Meyer's agent John Moore.
"We're able to deliver these hotels in around 16 months," he said, adding the project would create up to 35 permanent jobs.
London and Edinburgh already have floating hotels, he said, but this would be a first for Cardiff.
He described the plans as "unique" and "different", adding "the attraction of being on the water is the main thing".