Informal cross-border trade (ICT) is a significant aspect of regional integration in Africa, particularly within ECOWAS (Economic Community of West African States). Kenya's role as a gateway to East and Central Africa presents unique opportunities for analysing ICT dynamics. A mixed-methods approach was employed, integrating quantitative surveys with qualitative interviews to gather data from traders, border officials, and policymakers. Data analysis utilised descriptive statistics and thematic coding for thematic insights. The survey revealed a significant proportion (58%) of cross-border trade in Kenyan markets involves informal transactions, predominantly centred around agricultural products such as maize and livestock. Border regulatory inefficiencies are highlighted as major barriers to formalizing these activities. Informal cross-border trade remains a vital component of Kenya’s regional integration efforts, though it faces significant challenges related to regulation and enforcement. Policymakers need to address these issues to foster sustainable regional development. Implementing standardised regulatory frameworks, enhancing border management systems, and promoting intergovernmental cooperation are recommended steps for bolstering formal trade in ECOWAS regions.