The 85-room site will feature the award-winning Jetty restaurant concept and rooftop Champagne Bar, alongside the Harbour Spa with gym and swimming pool.
The ground floor is set to include an additional open plan lounge, restaurant and bar, which will extend out onto a terrace overlooking the water and allow private moorings for guests.
Following several years' planning the hotel will become the flagship site of the Harbour Hotels portfolio, which currently features five premium hotels across the south west.
Mike Warren, managing director of Harbour Hotels, said: “We are very confident that the hotel and its facilities will prove a fabulous addition to Southampton, boosting tourism and becoming a destination of choice for city-dwellers and visitors alike.”
The design of the premises will be nautically inspired with yacht chic décor.
The development is expected to take 18-24 months and has been welcomed by the local council which is keen to develop Southampton’s waterfront.