This paper provides the first systematic empirical assessment of how regulatory convergence within the COMESA–EAC–SADC
Tripartite Free Trade Area (TFTA) affects trade flows among the 29 Member/Partner States. Using a newly constructed dataset that
maps the harmonisation of technical regulations, sanitary and phytosanitary measures, rules of origin, and competition policy from
2010 to 2023, we estimate a structural gravity model augmented with time-varying indices of regulatory alignment. We find that
each standard deviation increase in regulatory convergence is associated with a 12–18 % rise in bilateral trade, with the largest gains
accruing to agricultural and processed-food products where standards previously diverged most sharply. The effect is strongest for
EAC members—who already share a relatively harmonised regulatory regime—and weakest for SADC exporters facing more
complex product-specific rules of origin. Counterfactual simulations suggest that full convergence to best-practice EAC levels could
expand intra-TFTA trade by up to 34 %, equivalent to an additional US $9 billion annually, and disproportionately benefit smaller
economies through improved market access and reduced compliance costs. However, residual non-tariff barriers, notably
administrative procedures and mutual recognition gaps, continue to mute the gains from regulatory harmonisation. Our findings
indicate that while the TFTA’s explicit focus on regulatory convergence is already bearing fruit, accelerating implementation of
common conformity-assessment procedures and digital NTB-monitoring systems will be critical for realising the arrangement’s
ambitious trade-creation potential.