In spite of abundant generation potential, as of 2019 East Africa has an electricity access level of 36%, with over 140 million people without service. Here, a bottom-up geospatial model (OnSSET) is used to estimate least-cost pathways to universal access to electricity by 2030 for different consumption-tier objectives under three regional grid electricity generation mix scenarios. Results suggest median total required investments of $57 and $110 billion for guaranteeing basic (160 and 44 kWh/person/year in urban and rural areas) and moderate-i.e. including potential to enable some productive uses-(423 and 160 kWh/person/year) consumption for newly connected households by 2030, respectively. This corresponds to an average of $5.6 billion/year, and implies median capacity additions of 12.2 GW (59% on-grid, 37% mini-grids, and 4% standalone solutions). At least further $2.7 billion/year in generation capacity are required to satisfy the projected demand growth from already electrified consumers. A grid electricity scenario with 25% lower photovoltaic costs and a higher penetration of renewables reveals to be up to 10% cheaper and 46% less carbon-intensive, while also requiring less up-front investment. To achieve such objectives, investment must be channelled within an enabling policy environment, which we discuss.