<p>Ocean acidification (OA) and nutrient enrichment can separately or together threaten coral reefs by reducing calcification efficiency and increasing physiological stress, ultimately weakening reef resilience. Therefore, the study evaluates the prevailing OA level over the Sri Lankan coral reef areas using the aragonite saturation state (Ω_Ar) and assesses the nitrate (NO₃⁻), and phosphate (PO₄³⁻) concentrations over the coral sites. The study was conducted on coral reefs on the eastern coast (EC), southern coast (SC), northern coast (NC), and west coast (WC) of Sri Lanka from April to June 2024. A total of 63 seawater samples were collected around each coastal site for analysis. The Ω_Ar were supersaturated (Ω_Ar &gt; 1) and ranged from 2.98 ± 0.04 to 4.92 ± 0.12. Throughout the study period, the study sites had Ω_Ar values exceeding 2.92 ± 0.16, indicating that the nation's corals were&#xa0;resilient to deterioration, and the comparative analysis demonstrates that these sites were not vulnerable to OA. However, the NC exhibited significantly (P &lt; 0.05) the lowest Ω_Ar values (3.2 ± 0.64), positioning the regions near the lower bound of optimal calcification conditions. While Ω_Ar values indicate low OA stress during sampling, elevated NO₃⁻ concentrations (2&#xa0;–&#xa0;5 μmol L⁻¹) in SC (2.19 ± 1.28 µmol L⁻¹) and WC (3.52 ± 1.48 µmol L⁻¹) may exacerbate coral bleaching during thermal stress events, representing a co-stressor rather than OA effect. Coral bleaching HotSpot (HS) identification emphasizes how spatially distributed HS are from January to June. The OA risk assessment confirmed that climate change will bring high risk to the coral calcification, reproduction, and damage to the breeding ground, which impact on the ecology and economy of Sri Lanka.</p>