Abstract: An underwater light includes a sealed housing defined by a rigid portion and a flexible portion. The rigid portion incorporates a light transmission window. A light source is mounted in the housing to direct its light through the housing's window. Also mounted in the housing are a power source and an open electrical circuit coupling the power source to the light source. The open electrical circuit includes spaced-apart terminals that prevent electrical power from being delivered to the light source. One of the terminals is coupled to the flexible portion of the housing and is aligned with another of terminals. Flexing of the housing's flexible portion into the housing causes the terminals to contact one another so that electrical power can be delivered to the light source. For depth compensation, a non-compressible dielectric fluid fills the housing.