The present application is directed to a subsea separator. The subsea separator suitably comprises (a) a housing having an inlet for receiving a fluid mixture, a non-gaseous fluid outlet located along the housing at a point lower than the inlet, and a gas outlet located along the housing at a point higher than the inlet; (b) a deflector means located within the housing for acting on fluid entering the housing; and (c) a sealing means in communication with the gas outlet for preventing non-gaseous fluid from exiting the housing through the gas outlet, the sealing means being operationally configured to open and seal the gas outlet based on the volume of non-gaseous fluid within the separator; wherein the separator is operationally configured to operate under a differential pressure including a greater external hydrostatic pressure than internal pressure and vice versa.