As infrastructure development accelerates, ensuring the quality of the subbase layer in roadworks has become increasingly vital. Among various evaluation tools, the Dynamic Cone Penetration (DCP) test is widely recognized for its practical advantages—namely its ease of use, affordability, and ability to deliver real-time, continuous assessments of soil strength directly on-site without disturbing the ground. The research involved conducting both DCP and SRM tests on subbase materials classified as types B, C, and D, which are frequently utilized in Basra’s Road construction. The investigation measured parameters such as the Dynamic Cone Penetration Index (DCPI), moisture content, and dry density under three distinct moisture conditions, all assessed within a controlled laboratory setting. Results were analyzed using SPSS (version 27), revealing a strong inverse relationship between dry density and DCPI, A direct correlation between DCPI and moisture content and between moisture content and dry density. Three predictive equations were developed for each subbase type. The approach has proven to streamline testing processes by minimizing time and resource demands, making it a credible and efficient alternative to conventional subgrade resistance methods for field-based soil assessment.