Abstract: An adjustable buoyancy fishing bobber is provided having a body portion of cylindrical shape with accordian pleated sides running the full length of the body portion. At one end the cylindrical body portion is closed with an axially extending round post projecting therefrom with a small ball at the end of the post. Passing through the center of the ball is a transversely extending round hole, and a slit extends from the side of the post inwardly to the transverse hole. The other end of the body portion is provided with a short threaded axial extension of smaller diameter for application thereto of a plastic screw-on closure cap. The bobber body is made of a soft flexible plastic which may be compressed along the accordian pleats. The fish line runs from the hook through the hole in the ball at the end of the round post, up and over the top of the threaded extension at the other end of the body portion, which is then clamped in place by a second snap-cap attached to the lower screw-on portion.