The world's largest underwater hotel is being planned for Dubai, with rooms both on the seabed and on stilts above the surface (+ slideshow).

The Water Discus hotel has been designed by Polish company Deep Ocean Technology (DOT), whose other ventures include designing underwater vehicles and equipment for seabed exploration.

The hotel will be made up of two main discs, one above the water and one below the surface, connected by five columns and a vertical shaft for the stairs and lift. Smaller circular volumes above the surface will contain additional facilities, with a helicopter landing pad mounted on one.

The lower disc will comprise 21 hotel rooms with underwater views, an underwater diving centre and a bar. Each of the surrounding discs will be able to detach from the main upper disc to be used as a buoyant life raft in case of emergency or flooding.

The diving centre will be accessed through an underwater airlock, leading divers straight into the ocean. There'll also be a decompression chamber for training purposes, DOT explains, while guests will also be able to take a course in piloting an underwater vehicle.

The modular construction of the hotel will enable it to be expanded or even moved to a new location, according to DOT.

The Water Discus won't be the world's first underwater hotel – there is already one in the Maldives and another in Florida. However, it will be the world's largest and the first to be built in Dubai.

Other unusual hotels we've featured on Dezeen include an ice hotel in Lapland and a mobile hotel room that can be delivered to any location – see all hotels.

Two of the ten tallest skyscrapers set for completion in 2013 are located in Dubai – the 355-metre-high JW Marriott Marquis Hotel and the 328-metre-high Al Yaqoub Tower.

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Images are by Deep Ocean Technology.