Self-curing composites autonomously undergo the curing process without external interventions, making them ideal for applications in inaccessible locations. This study examines the effect of areca microfibres (AMF) on the self-curing behaviour of cementitious composites. The study investigates the self-curing characteristics of concrete using a mix design consisting of 749 kg/m3 of cement, 1118 kg/m3 of fine aggregate, and 299 kg/m3 of water, with a water-cement ratio of 0.4. Experimental analysis evaluates fresh and hardened properties using two fibre size ranges: 2.36–1.18 mm and 1.18 mm–600 μm. Microfibres, pre-saturated for 24 h, are incorporated at 0.5, 1.0, and 1.5% volume fractions. The study aims to determine the optimum microfibre dosage for enhancing self-curing efficiency based on compressive strength performance. The experimental results are benchmarked against both conventionally cured composites and self-cured composites incorporating polyethylene glycol (PEG) to evaluate the effectiveness of areca microfibres as a self-curing agent. A comparative analysis of strength development reveals that concrete specimens containing pre-saturated areca microfibres exhibit notable improvements in compressive strength. Specifically, the self-cured specimens with 24-h saturated microfibres achieved up to 105% of the compressive strength of the water-cured control mix. AMF incorporated composites yielded curing properties comparable with 0.5% PEG as a chemical curing agent. This indicates that areca microfibres not only facilitate internal curing but also enhance the overall hydration process, potentially compensating for moisture loss through a sustainable practice.