Abstract: An adjustable depth marker buoy for marking a spot beneath the surface of water. The buoy includes a float for floating on the surface of the water and a reel assembly disposed in the float. The bottom wall of the float has a weight depending therefrom that maintains an upright orientation for the buoy when it is in the water. The reel assembly includes a spool of anchor line, a non-threaded rod, a threaded rod, a nut assembly that threadably moves along the threaded rod and slidably along the non-threaded rod, and a pointer assembly that moves slidably along the non-threaded rod. When the spot is located, its depth is determined. The pointer assembly is then slide along the non-threaded rod, until its pointer points to depth scale indicia on the depth plate corresponding to the depth of the spot beneath the surface of the water.