Achieving universal access to electricity by 2030 remains a critical challenge in Ecuador, especially in remote and ecologically sensitive areas such as the Galápagos Islands and the Amazon region. This study applies the Open Source Spatial Electrification Toolkit (OnSSET) to develop geospatial least-cost electrification scenarios for Ecuador under 2030 and 2050 timeframes. By integrating national and global open-access datasets, the analysis simulates grid expansion, off-grid, and photovoltaic hybrid mini-grid (MG-PV) solutions to reach underserved populations. Results show that by 2030, grid densification remains the dominant strategy, accounting for over 85% of new connections and requiring an investment of approximately USD 5.6 billion. However, decentralized hybrid systems, particularly MG-PV are essential for cost-effective electrification of isolated communities, serving more than 390,000 people. The 2050 scenario projects continued diversification, requiring over USD 65 billion in cumulative investments. This study demonstrates how open geospatial data and tools such as OnSSET can support evidence-based policymaking aligned with SDG 7 and Ecuador’s national decarbonization agenda.