Abstract: A streamlined annular buoy for marine pipelines includes a first annular buoy half comprising syntactic foam, where the first buoy half includes a substantially planar exterior first mating surface that includes an axial first channel formed therein and a first domed exterior surface radial to the axial first channel. Buoy also includes a second annular buoy half comprising syntactic foam, where the second buoy half includes a substantially planar exterior second mating surface that includes an axial second channel formed therein and a second domed exterior surface radial to the axial second channel. A fastener secures the first and second annular buoy halves together around a pipe that passes through a pipe channel formed by the axial first and second channels, such that the exterior first and second mating surfaces are face-to-face.