This paper presents a handheld guided wave testing probe, measurement procedure, and image processing algorithm to detect and locate defects in carbon fiber-reinforced (CFRP) structures. This study was performed by collecting data from a network of piezoelectric sensors controlled in a pairwise pitch-catch configuration. The probe includes sixteen piezoelectric elements spatially distributed in a square shape configuration to generate and receive ultrasonic guided waves (UGW) signals in the vicinity of a region to be inspected. Instead of collecting all the sensor combinations for defect detection, a measurement procedure is presented to record UGW signals from pairs of sensors that share identical distances and path conditions in the square shape configuration of the proposed probe. Additionally, a comparison between both baseline and baseline-free approaches is performed using the Reconstruction Algorithm for Probabilistic Inspection of Defects (RAPID) algorithm for defect detection, localization, and evaluation in a quasi-isotropic CFRP plate.