This research investigates the relationship between Islamic fintech, Islamic financial literacy, and religiosity and their impact on sustainable Islamic financial transactions within the Islamic banking context in Saudi Arabia. Employing a quantitative research approach, the study focuses on customers of Saudi Islamic Banks in Riyadh. The findings reveal nuanced insights. Firstly, Sharia financial literacy is determined to have no direct influence on Sharia financial transactions in Islamic banks in Saudi Arabia. Secondly, religiosity is found to have no direct effect on Sharia financial transactions. Thirdly, Islamic financial literacy significantly influences Islamic financial transactions, while religiosity does not exhibit a direct impact on Islamic fintech. Moreover, Islamic fintech is identified as a significant driver of Sharia financial transactions. Intriguingly, it is established that Islamic fintech mediates the relationship between Sharia financial literacy and financial transactions. However, no such mediating effect is observed in the case of religiosity influencing Sharia financial transactions. These results contribute to the growing body of literature on sustainable Islamic banking, clarifying the complex dynamics between Islamic Fintech, financial literacy, and religiosity as they influence the conduct of financial transactions within the context of Saudi Islamic banks in Saudi Arabia