Recent studies on slope failures in the Midwestern states have shown a substantial difference between the measured strength at the design stage and the back-calculated strength of the failed slopes. The reduced strength may be related to the region’s geological history, and it is called the wet-drained-fully softened shear strength. Laboratory techniques applied to evaluate this strength are time-consuming and expensive. On the other hand, field techniques have not yet been appropriately developed to evaluate this strength for soils above the groundwater table. This study proposes an innovative CPT-based technique to evaluate the fully softened shear strength in the field by utilizing a special wetting cone to inject water into the soils at the desired depth and achieve soil disturbance resulting from the penetration of the cone. Field CPT test results from test locations showed a significant decrease in tip resistance and sleeve friction by wetting the soils, indicating that the innovative use of the CPT method could measure the fully softened strength.