A fly fishing float and/or strike indicator is attached by an interference fit to a leader, by sliding the float up the leader to a thicker-diameter portion of the leader for a tight fit, and preferably a leader-compressing fit, between the leader and an axial bore in the float. A bore surface, that is non-compressible and/or less compressible than the leader, may be supplied as an insert around which a buoyant main body of the float is formed. The insert may also have features that prevent separation of the main body from the insert and that help transmit force on the main body to the bore surface for quick and efficient securement of the float to the leader by the interference fit.