This study assesses the hydrochemical dynamics of the "Arroyo Grande" aquifer near Cartagena de Indias, Colombia. The aquifer covers an area of 143 km2 and is characterized by sedimentary rock formations consisting of gravel and sand. Two field campaigns were conducted to analyze HCO3-, CO3-, SO42-, Cl-, NO2-, NO3-, PO4, Ca2+, Mg2+, Na+, Fe+, NH4+, Mn+, P, As, Hg, Pb, Se, NKT, total hardness, alkalinity, pH, temperature, electrical conductivity, salinity, dissolved oxygen, ORP, and SDT concentrations. The results show that The dominant anions observed were Bicarbonate (HCO3-) with concentrations ranging from 78.77 to 210.26 mg/L (dry season) and 95.85 to 215.02 mg/L (wet season), Chloride (Cl-) ranging from 61.7 to 234 mg/L (dry season) and 57.1 to 226.9 mg/L (wet season), and Sulfate (SO42-) with concentrations ranging from 31.8 to 177.9 mg/L (dry season) and 29.86 to 303.65 mg/L (wet season). Additionally, Sodium (Na+) ranged from 40.3 to 61.68 mg/L (dry season) and 47.97 to 104.40 mg/L (wet season), Calcium (Ca2+) concentrations ranged from 23.22 to 42.25 mg/L (dry season) and 33.13 to 62.43 mg/L (wet season), and Magnesium (Mg2+) concentrations ranged from 8.76 to 29.63 mg/L (dry season) and 9.94 to 50.11 mg/L (wet season). In conclusion, the studied aquifer is mainly influenced by mineral dissolution, ion exchange, salinization resulting from seawater intrusion, and anthropogenic contamination.