Abstract: A locking apparatus for use with surfboards and other articles which attaches to a cross bar on the article. The locking apparatus includes a member which surrounds the cross bar and a means for locking and unlocking the member to the cross bar thereby preventing unauthorized persons from removing the member from the cross bar. Used with a conventional surfboard, the lock apparatus advantageously attaches to an existing leash plug cross bar, requiring no modification or retrofit to the surfboard, and attaches without removal of a leash cord which likewise typically attaches to the cross bar. Further, a cable secures to the locking apparatus and is looped around or affixes to a generally stationary structure, such as an automobile surfboard roof rack, bicycle rack, post, etc., in order that the article cannot be moved without first unlocking the member.