<p>Significant wave period is an important parameter in coastal and offshore engineering design. Traditional spectral wave models do not directly calculate this parameter, which means that it needs to be estimated from the spectral periods using empirical formulas. The wave energy period is one of the wave periods directly output by many wave models and is often used in studies of wave energy. This study investigated the relationship between significant wave period and wave energy period using wave data measured at three stations in the coastal waters of China. The observations recorded at these stations in the South China Sea, the East China Sea, and the Bohai Sea covered a wide range of surface wave conditions. Analysis indicated that the ratio of significant wave period to wave energy period is closely related to the Goda peakedness parameter of the wave spectra. Therefore, we proposed an empirical formula in which significant wave period is a function of wave energy period and the Goda peakedness parameter. Evaluation results showed that the performance of this formula is substantially better than that of fitting formulas that use constant coefficients.</p>