Saudi Arabia’s cashless transition has moved from a policy aspiration to a measurable structural shift within retail payments, digital commerce, and platform-based financial services. This review examines how fintech payment solutions, including national card rails, mobile wallets, instant payments, open-banking interfaces, merchant acceptance technologies, and embedded checkout tools, are accelerating the Kingdom’s cashless economy agenda under Vision 2030. Using a structured narrative review approach guided by a source-screening protocol and a synthesis framework centred on adoption drivers, ecosystem enablers, and implementation barriers, the paper integrates evidence from policy reports, market studies, and recent peer-reviewed research published between 2020 and 2025. The review finds that Saudi Arabia’s progress is not explained by consumer preference alone. It is the product of coordinated public policy, robust payment infrastructure, high smartphone penetration, bank-fintech collaboration, contactless acceptance, regulatory experimentation, and trust-building around security and convenience. Fintech payment solutions speed checkout, widen formal transaction capture, reduce cash handling frictions, support e-commerce conversion, and generate data flows that improve risk management, financial inclusion, and service personalization. At the same time, the transition remains uneven across merchant categories, age groups, business sizes, and use cases. Cybersecurity concerns, compliance burdens, digital capability gaps, and interoperability issues continue to influence adoption depth. The paper concludes that the next phase of acceleration will depend less on basic access and more on ecosystem quality: seamless merchant onboarding, open-banking payment initiation, consumer trust, resilient cyber controls, and targeted inclusion strategies for micro-enterprises and lower-intensity digital users. The review contributes a Saudi-specific framework linking fintech payment innovation to transaction formalization, retail efficiency, and broader economic modernization.