The Jules Undersea Lodge is a very unique hotel in Key Largo, Florida. It is best known for its location, which is underwater.

Noted for being the only underwater hotel in the United States, the Jules Undersea Lodge is located at the bottom of the Emerald Lagoon. It was opened in 1986 and requires guests to scuba dive to get to the rooms. Everyone is welcome, though, because scuba certification is not required, as the entrance of the front door is only at 21 feet under water.

The Jules Undersea Lodge traces its roots to the creation of one of the most advanced research habitats ever created, the La Chalupa underwater research laboratory, created in the 1970s. Research projects still take place at the laboratory.