Methods, systems, and devices for wireless communication are described. A wireless device may communicate using a dynamic cyclic prefix (CP) length to reduce communications overhead. That is, the wireless device may use a CP length that is changeable for each data packet or listen-before-talk (LBT) frame. For example, the wireless device may initially communicate using a first CP length and then receive a dynamic CP indication for subsequent symbols in one or more data packets or LBT frames. The wireless device may then communicate using the different CP length based on the indication. In some examples, the indicated dynamic CP length may be based on a cell radius of a base station, a data direction, or the location of a user equipment (UE) in relation to the base station.