The present invention relates to an underwater excavation apparatus. The apparatus of the invention utilizes mass flow for disturbing or excavating an underwater location and for extracting or sucking excavated material from the underwater location to another location. Restriction of spoil and/or direct spoil is provided for the apparatus and comprises a baffle provided within a cavity of a housing having an open base for the extracting or sucking of excavated material. An outlet for disturbing or excavating and an inlet for extraction or suction are located within the housing while an inlet for disturbing or excavating and an outlet for extraction or suction are located external to the housing.