The UK cinema version was cut by 19 secs by the BBFC and completely removed the scene of Johnny rolling and lighting a reefer for a PG certificate. Later video releases were uncut and the certificate upgraded to 15.
NBC edited 6 minutes from this film for its 1987 network television premiere.
AMC's airing of the film cuts out the scenes in which Johnny and friends talk to Alli and Daniel outside Golf N Stuff, and the scene in which Miyagi deals with the delinquents setting beer bottles on his car.
Also cut from AMC airings are the scenes in which Daniel talks to a history teacher, the bathroom footage of Johnny rolling a joint (though the action is still referenced), and a frame in the scene where Miyagi rescues Daniel from the Cobra Kai guys (the frame of Miyagi kicking one of the guys in the crotch area is removed.)
The edited-for-TV versions are heavily edited for drugs and violence. The scene where Johnny is rolling a joint in a cubicle is snipped, and we just see Daniel feeding the hose through the top of the door. Many of the fight scenes are clipped, cutting away most of the action and actual punches are not shown. The final move by Daniel is shown, but the immediate reaction of Johnny (and his rolling on the floor in pain) is not