This paper studies the sustainability of preschools established under a large-scale project in rural Indonesia. We returned to project villages three years after the project closed to understand why some preschools were able to sustain operations while others closed. We present four key findings. First, 92 per cent of preschools from the project remained open three years after project funding ended. Second, preschools planned for sustainability by taking into account six factors: preschool quality, finance, supplementary services, market condition, household wealth, and parental involvement. Third, each of these factors predicts sustainability after project closure. Finally, interviews with former teachers show that the few preschools that closed were those that struggled to find both the financial and human resources needed to continue operating. We discuss actionable lessons for the design and sustainability of future early childhood education projects.