This study examines the interoperability of cross-border Quick Response (QR) payment systems within Association of Southeast Asian Nations plus China, Japan, and South Korea (ASEAN+3), focusing on how national infrastructures are linked to enable seamless retail transactions. As QR adoption accelerates across Asia, integration between systems such as Malaysia’s DuitNow, Indonesia’s Quick Response Code Indonesian Standard (QRIS), Singapore’s Network for Electronic Transfers (NETS), Thailand’s PromptPay, and Cambodia’s Bakong has become central to advancing financial inclusion and regional connectivity. Given the nascent stage of regional integration and limited empirical transaction data, this study employs a qualitative, narrative-based approach grounded in secondary data and policy documents to critically review existing national systems and map interoperability gaps. Accordingly, thematic analysis revealed four dimensions shaping readiness and integration: Technological interoperability, regulatory and policy alignment, market adoption, and systemic challenges. Concurrently, findings reveal that while bilateral QR linkages are operational in several jurisdictions, disparities remain in coverage, transaction limits, and regulatory harmonisation, particularly in emerging markets. In particular, Malaysia’s DuitNow QR is highlighted as a strategic case, demonstrating how national systems can serve as gateways for regional integration. Additionally, recommendations emphasise the need for ISO 20022 harmonisation, reciprocal regulatory cooperation, and inclusive digital infrastructure to support broader multilateral platforms. Thus, the study underscores the significance of cohesive regional strategies to achieve a financially integrated and digitally inclusive ASEAN+3 ecosystem.