<p>Precast segmental post-tensioned concrete beams (PSBs) may benefit from the use of carbon fiber-reinforced polymer (CFRP) to improve their structural performance, especially around the joints where stress concentrations and failure tend to arise. This paper reports on an examination into the impact of externally applied CFRP strengthening on the flexural characteristics of PSBs subjected to four-point bending under varying joint configurations. A total of six full-scale specimens were subjected to tests, consisting of dry-jointed and epoxy-jointed PSBs with plain or shear-keyed interfaces. A portion of the dry-jointed PSBs was strengthened on their tension face using CFRP sheets. The tests indicate that CFRP strengthening significantly improves flexural capacity and ductility of PSBs. Compared to unstrengthened dry-jointed specimens, CFRP strengthening increased flexural capacity by 26% and 36% for plain and shear-keyed joints, respectively. The ductility was improved by 8% and 37% for the same. Additionally, initial CFRP strengthening led to 103% and 56%, respective increases in initial stiffness, better resisting early-stage deflections. Apart from optimised ultimate behaviour, the CFRP strengthening was found to modify failure modes from sharp opening of the joint to progressive flexural-dominated failure. Comparative analytical assessment utilising AASHTO code provisions demonstrated a safe margin of up to 13% when estimating the ultimate limit-state strand stress. These tests demonstrate the effectiveness of CFRP strengthening in upgrading the serviceability and structural capacity of precast segmental concrete beams, particularly in the environment of dry-jointed connections. The study contributes evidence towards the increased application of CFRP retrofitting among segmental bridge schemes.</p>