<p>The rapid growth of Indonesia’s construction sector has led to increased demand for sustainable and cost-effective infrastructure solutions, particularly for road pavements. This study aims to bridge the gap in understanding the trade-offs between embodied carbon and construction costs in flexible and rigid pavements in Indonesia, offering a novel framework for integrating environmental and economic considerations in pavement design. A comprehensive methodology was developed to design flexible and rigid pavements per Indonesia’s national standards, with variations in sub-base materials, including cement-treated bases (CTB) for flexible pavements and both CTB and lean mix concrete (LMC) for rigid pavements. The results demonstrate that flexible pavements with CTB exhibit the lowest embodied carbon (40 kgCO₂e per m²), whereas rigid pavements, particularly those with LMC, have higher embodied carbon (108 kgCO₂e per m²). Cost analysis revealed that flexible pavements with CTB are the most cost-effective option (588,200 IDR per m²), whereas rigid pavements with CTB have the highest costs (707,400 IDR per m²). These findings highlight a critical trade-off: flexible pavements offer a favourable balance between sustainability and cost, whereas rigid pavements are less sustainable and more expensive. This study contributes to the state of the art by introducing a reproducible framework for evaluating pavement design and advancing the discourse on sustainable infrastructure development. Policymakers and industry practitioners could leverage these insights to align infrastructure projects with sustainability targets and economic constraints.</p>