The entrepreneurial landscape in East Africa is complex, yet qualitative insights into the lived experiences of business owners navigating this ecosystem remain limited. Understanding the interplay between systemic challenges and individual agency is critical for fostering sustainable enterprise development. This study aimed to explore the nuanced challenges and perceived opportunities encountered by Tanzanian entrepreneurs, with the objective of identifying key leverage points for ecosystem support and policy intervention. A constructivist qualitative study was conducted using in-depth, semi-structured interviews with 28 purposively sampled entrepreneurs across three regions. Data were analysed using reflexive thematic analysis to develop interpretative themes. A predominant theme was the critical, yet often obstructive, role of informal financial networks, with over two-thirds of participants describing a heavy reliance on rotating savings and credit associations (ROSCAs) due to formal credit exclusion. Entrepreneurs framed these networks simultaneously as a vital lifeline and a source of social pressure. The findings illustrate a dualistic entrepreneurial ecosystem where informal institutions fill significant gaps left by formal structures, creating a resilient but constrained operating environment for business growth. Policymakers and development practitioners should design financial products that formally integrate or partner with trusted informal mechanisms. Business development services must address the socio-cultural dimensions of entrepreneurship, not just technical skills. entrepreneurship, qualitative research, business ecosystem, informal finance, Tanzania, thematic analysis This paper provides a novel, empirically-grounded typology of entrepreneur responses to institutional voids, moving beyond a simple deficit model to highlight adaptive hybrid strategies.