The solubility of dilute SO2 in seawater, from mixtures SO2 + N2, was determined in a temperature range between (278.15 and 318.15) K and a SO2 partial pressure range between (0.050 and 1.5) kPa. Measurements were carried out by a saturation method using a laboratory-stirred batch reactor. Equations to correlate experimental data were obtained as a function of temperature and SO2 partial pressure. Comparisons between experimental results, literature data, and theoretical predictions were also made at different temperatures. Two different models were considered to evaluate the activity coefficients of ionic species. Theoretical calculations were made using both an extended version of the Debye−Hückel theory and the Pitzer ion-interaction model. Both models led to similar predictions and were in good agreement with the experimental results. The reasonable fitting between measured and calculated data showed that the selected models can be successfully used for predicting the absorption equilibria of dilute sulfur dioxide in seawater at different temperatures.