This study investigated the influence of mineral admixtures (fly ash, silica fume, metakaolin) and curing conditions (water immersion, polyethylene glycol, gunny bags, accelerated curing) on the properties of self-compacting concrete (SCC). The rheological properties, compressive strength, chloride penetration resistance, and microstructure were evaluated. Incorporating mineral admixtures improved the workability, strength (up to 53% increase), and durability of SCC compared to plain mixes, with 20% metakaolin replacement optimal. Water immersion curing enhanced the compressive strength (3–15% increase) and chloride resistance (up to 30% decrease in migration coefficient) owing to improved hydration and microstructural refinement. Mineral admixtures reduced the sensitivity of SCC to the curing method. Microstructural analysis showed higher density and additional C-S-H phases with mineral admixtures under wet curing. The study demonstrates that optimized SCC containing appropriate supplementary cementitious materials and proper external curing can achieve high performance.