This study investigates the challenges confronting flexible pavements in India, encompassing issues such as heavy traffic wear, inadequate drainage, and harsh climatic conditions. With limited resources and expertise exacerbating maintenance problems, and construction methods often contributing to environmental degradation, the research explores the viability of using coir fibre, derived from coconut husks, as an eco-friendly reinforcement for these pavements. By integrating coir fibres into pavement mixes, the study aims to mitigate environmental impact, enhance structural strength, improve drainage, and reduce construction costs. Marshall stability tests are conducted to determine the optimal fibre content, with variations tested at 0.2%, 0.4%, and 0.6% by total weight of aggregate, while maintaining a consistent fibre length of 10 mm. Results indicate varying stability and flow values corresponding to different fibre percentages. By identifying the optimal fibre and binder contents, this research contributes to sustainable pavement construction and offers a cost-effective approach to infrastructure development. The insights gained into the comparative strength and stability of pavements reinforced with natural fibres provide valuable information for future environmentally conscious pavement design, ultimately aligning with India’s aspirations for sustainable development and environmental stewardship in transportation infrastructure. The study finds that 0.2% coir fibre content and 5.32% bitumen content are optimal based on the Marshall stability test, underscoring the efficacy of coir fibre reinforcement in flexible pavement construction.