This disclosure provides systems, methods, and apparatuses for a beam-based channel access countdown procedure. In one aspect, a channel sensing beam may be permitted to include one or more transmit beams and, thus, may differ from a transmit beam that is to be used for a transmission. As such, defining a manner in which a channel access countdown procedure is performed is desirable. Some aspects described herein provide techniques and apparatus for a beam-based channel access countdown procedure. In some aspects, the systems, methods, and apparatuses described herein provide a beam-based channel access countdown procedure that allows a single channel sensing beam, including multiple transmit beams, to be utilized in association with determining channel availability for the multiple transmit beams, thereby improving performance of beam-based directional transmissions.