This study proposes a novel wireless guided-wave ultrasonic propagation imaging (GUPI) system to enable completely wireless inspections of structures. A conventional GUPI system consists of an excitation laser, laser mirror scanner (LMS), computer with data acquisition (DAQ) capability, bandpass filter, and sensor. While the GUPI system offers a fast scan time and a large scan area compared to other laser scanning or non-destructive testing systems, the physical wired connection of the sensor to the DAQ remains an obstacle for in situ implementation. Therefore, in this study, a wireless ultrasonic device (WUD) and peak detection-based wireless synchronization algorithm were developed for a wireless GUPI system, which eliminated the physical wired connection between the specimen and inspection system. A composite wing skin specimen was used to compare wired and wireless GUPI system measurements. The wireless inspection capability of the wireless GUPI system will improve the possibility of implementing the GUPI system for aircraft structure inspections and enhance the overall structural safety of the aircraft.