This assessment of ocean acidification at Flic-en-Flac (FF), located in the west of Mauritius, is a first-time study conducted from 2017 to 2021. The variations of pH and total alkalinity (A_T) were monitored. Over the course of this study, temperature varied from 23 °C to 31 °C, whereas salinity was constant at 35 %. The summer season lasted from October to March and the winter season from April to September. The lowest mean pH value, (7.94 ± 0.02), was noted in April 2019 winter month whereas the highest mean pH value (8.17 ± 0.03) was noted in October 2017 summer month. The overall mean pH values (8.06 ± 0.06) were slightly higher in all summer periods compared to winter ones (8.01 ± 0.07). However, it was observed that the mean pH values in summer 2018 (7.97 ± 0.03), were lower than in 2017 (8.06 ± 0.06) and 2019 (8.03 ± 0.05) due to a tropical storm. The mean A_T for the three sampling periods was (2404.1 ± 174.8) µmolkg⁻¹ , in line with the global mean of (2300 ± 200) µmolkg⁻¹ . The mean alkalinity varied from (2094.8 ± 68.0) µmol/kg (September 2019) and the highest mean AT of (2880.0 ± 14.1) µmol/kg (November 2018). In most cases, results following the t-test show that they were significant when the pH values of summer and winter were compared. However, all the t-test results were not significant with regards to alkalinity.