Financial inclusion remains a critical development challenge in sub-Saharan Africa, with rural populations disproportionately excluded from formal financial services. The rapid proliferation of mobile telephony has created new pathways for service delivery, yet comprehensive longitudinal data on adoption drivers and impacts in rural settings is limited. This study aims to analyse the determinants of mobile banking adoption among rural households and to assess its impact on key financial inclusion metrics, including savings behaviour, access to credit, and resilience to economic shocks. A stratified multi-stage random sampling survey was administered to 1,200 households across six agro-ecological zones. The survey instrument captured quantitative data on usage patterns, perceived barriers, and socio-economic characteristics, complemented by qualitative focus group discussions. Data analysis employed logistic regression and thematic analysis. Adoption rates increased significantly over the study period, with 78% of households using at least one mobile banking service by the final survey wave. The primary driver of sustained use was the perceived reliability of transactions, while the most significant barrier remained the cost of airtime and transaction fees. A positive correlation was found between mobile banking use and informal savings group participation. Mobile banking is a potent catalyst for financial inclusion in rural areas, but its benefits are moderated by cost sensitivity and infrastructure constraints. Adoption follows a diffusion pattern influenced more by practical utility and social networks than by demographic factors alone. Policymakers and providers should develop targeted subsidy programmes for transaction fees and invest in agent network liquidity in remote areas. Financial literacy initiatives must integrate digital product education to build trust and competency. financial inclusion, mobile money, technology adoption, rural finance, survey research, Kenya This paper provides a novel six-year longitudinal dataset tracking the evolution of mobile banking adoption, uniquely capturing the shift from initial uptake to embedded use and its subsequent effects on household financial portfolios.