Shortages of river sand impede the construction industry’s ability to procure high-quality fine aggregates for concrete. This problem compels scholars to explore alternatives to river sand for construction purposes. Despite the widespread utilization of M-sand, it is not a viable alternative. The construction business is progressively pursuing alternatives. The main objective of the study is to investigate sustainable alternative fine aggregates that can substitute M-sand. A comparative investigation on the strength properties of concrete incorporating M-sand, pond ash, and steel slag has been conducted. The study showed that steel slag possesses greater angularity, a rougher surface, and a larger total specific surface area, in comparison to pond ash, which is inherently smoother. For conventional M25 grade concrete in comparison to M-sand, these alternative aggregates exhibit superior strength and enhanced concrete properties. Fine particles diminish the workability of concrete across diverse mix patterns. Concrete formulated with only pond ash exhibits a 60 % increase in compressive strength for 30 % replacement, and a mixture containing 10 % pond ash and 50 % steel slag demonstrates approximately 49 % enhanced strength due to the angular and rough particles that augment the strength of alternative fine aggregate combinations, albeit without improving workability. Steel slag and pond ash can substitute for M and river sand. This study may address the deficiency of river sand and M-sand in the market.