Proposed in 2006, the proposed underwater hotel for Fiji known as Poseidon Resort Mystery Island has released new designs. Although it is still seeking funding to support the development you can now start saving your pennies for this vacation paradise. They estimate it will cost $30,000/couple for a week.
Jules Undersea Lodge - Key Largo, Florida Jules Undersea Lodge is 21 feet under the ocean's surface, and you'll enter the lodge through an opening in the hotel floor. Originally an underwater research laboratory, the lodge rests in a mangrove lagoon, which serves as a natural nursery for reef fish like parrotfish, snapper, tropical angelfish, oysters, and anemones. Guests at the lodge are allowed an unlimited number of tanks for the hotel-provided scuba gear.