Routine hospital records classify waste by hazard and rarely identify non-infectious medical plastics (NIMP) as a distinct material stream, leaving circularity opportunities unmeasured. This study developed a hospital-level circular economy (CE) indicator framework for NIMP and assessed its applicability at two Thai tertiary hospitals. A structured review of 24 source documents yielded 375 indicator records, which were consolidated into 53 candidates and screened to 36 indicators across Material Circularity (16), Operational Integration (11), and Policy and Governance (9). Each indicator was assessed at each site against available evidence, from routine records and documents to field sorting and weighing, and classified as Ready, Hospital-level proxy, or Data-limited. Of the 36 indicators, 27 at Site A and 24 at Site B were represented as a value or proxy; the remaining nine and 12 were data-limited, and the same nine indicators were data-limited at both sites. The pattern was consistent across the two sites despite their different record systems: field-measured material and document-based governance indicators could be measured directly, whereas indicators requiring NIMP-specific data could not. The framework provides a practical basis for assessing readiness for routine NIMP circularity reporting and identifying priority data gaps.