A buoyancy module comprises a multi-layer outer protective shell that has an exterior surface and an interior surface. A first layer of foam buoyancy material is located adjacent to the interior surface. A second layer of foam buoyancy material that includes macrospheres and syntactic foam is surrounded by the first layer of foam buoyancy material. The multi-layer outer protective shell can include a layer of fiberglass backed by a fibrous plastic liner. In this embodiment, the layer of fiberglass provides the exterior surface of the multi-layer outer protective shell, while the fibrous plastic liner provides the interior surface of the protective shell. The second layer of foam buoyancy material can be a precast material. The precast material can include for example macrospheres and syntactic foam. The first layer of foam buoyancy material is preferably a stronger layer than the second layer of foam buoyancy material. Advantageously, the buoyancy module has a plurality of different layers, wherein the components of greatest strength and density are located on the outside. The multi-component system improves ruggedness of the buoyancy material, and provides increased reinforcement at locations subject to increased bending strengths, and provides a buoyancy module of longer life. In addition the buoyancy module may also include steel support members where bolting loads and other forces are brought to bear when parts are attached.