This paper maps the economic, legal, and political contours of a potential tripartite Free Trade Agreement (FTA) that would merge
the 21-member Common Market for Eastern and Southern Africa (COMESA), the 7-member East African Community (EAC), and the
16-member Southern African Development Community (SADC). Using an approach that combines computable general-equilibrium
(CGE) modelling, legal-textual analysis of existing protocols, and elite-level stakeholder interviews, we estimate that full liberalisation
of goods, services and factor markets could raise intra-African trade by 28–35 % and add 1.2–1.8 % to regional GDP within ten
years. However, gains are asymmetric: coastal economies with large manufacturing bases (Kenya, South Africa) would expand
output by up to 5 %, while several land-locked least-developed members face adjustment costs exceeding 2 % of GDP unless
flanked by robust rules of origin, trade-facilitation and compensation mechanisms. We find that overlapping memberships already
create an average tariff preference erosion of 6 percentage points and 134 conflicting rules of origin, implying transaction costs of
roughly US $420 million annually. A consolidated Tripartite FTA could eliminate these distortions, but only if it adopts a common
external tariff architecture, harmonises sanitary-phytosanitary standards and introduces a single digital certificate of origin. Political-
economy simulations reveal that coalition formation follows a North–South cleavage: resource-rich SADC states demand flexibilities
for sensitive products, while EAC pushes for deeper services liberalisation. To overcome deadlock, we propose a phased integration
blueprint: Phase I (2026-30) consolidates tariff schedules; Phase II (2031-35) negotiates services, investment and competition;
Phase III (2036-40) establishes a continental customs union. The paper concludes with a risk matrix that weights implementation
scenarios against AfCFTA convergence timelines and offers policy recommendations for sequencing, dispute settlement and
adjustment financing.