The current study explored the valorization of crushed blood clam shells (Anadara granosa) as an alternative fine aggregate replacement in the production of self-compacting mortar (SCM). In this experimental study, the blood clam shells were crushed and sieved, thus becoming blood clam shell fine aggregate (SFA). The SFA was utilized to substitute partially natural fine aggregate (NFA) in the amounts of 0 to 30 wt.%. The expected fresh properties of SCM on each SFA replacement level were designed using specifications from the European Federation of National Associations Representing for Concrete (EFNARC) by assessing its filling ability with mini-slump flow and its passing ability with the mini V-funnel test by adjusting the superplasticizer amount. The SCM’s properties were studied using its compressive strength and splitting tensile strength. The results demonstrated that the effect of SFA partial replacement on NFA on the mechanical properties of hardened mortar at 28 days at variations of 0 wt.%, 10 wt.%, 20 wt.%, and 30 wt.% had values of 56.0 MPa, 53.0 MPa, 56.2 MPa, and 58.2 MPa, respectively, for compressive strength and 3.6 MPa, 3.5 MPa, 4.5 MPa, and 3.9 MPa, respectively, for splitting tensile strength. By comparing it with SCM that employ full NFA, the SCM with SFA replacement at the amount of 20 wt.% could be obtain the equivalent compressive strength and about 25.91% higher splitting tensile strength.