Fintech, a leading force in banking innovation, is crucial in fostering sustainable finance. This study explores whether the collaboration between Fintech companies and small banks contributes to sustainable finance in India. Using an exploratory research design, Equitas Small Finance Bank (ESFB) is the focal point, with data collected through surveys and interviews. Results indicate that collaboration yields improved customer services, expanded mobile banking capabilities, and reduced operational costs. However, it also introduces new risks, including liquidity, cybersecurity, and legal concerns. Nonetheless, opportunities abound, including biometric authentication for security, agent banking solutions, solar-powered ATMs, and health tech via mobile banking for rural populations. To ensure sustainable finance, assessing the economic, social, and environmental impacts of Fintech applications on banking operations and customer services is imperative. This holistic approach will empower ESFB to deliver enhanced rural banking services responsibly.