Abstract: Artificial reef structures include various building components that are performed from concrete and the like. The components include square blocks having mounting grooves on the upper and lower surfaces. The blocks can include a center base plate, a circular opening instead of a center base plate, or be completely hollow. Optional metal bolts can be threaded through the center base plate. A hollowed out dome structure component includes through-holes and triangular type side openings. An arch component includes ribs separated and connected together by perpendicular rectangular beams. All the structure components can be used separately by themselves, in identical groups or in combination with one another either stacked or interlocked. For example, the blocks can be interlocked together with two blocks side by side and connected together by at least a third block on a second level. The domes can be fit over the blocks. The arch component can be positioned over the blocks as well.