A strong linear relationship is found between the transport through the Korea Strait and the sea level difference (SLD) between Moji, Japan and Pusan, Korea after a correction is applied to SLD using cross-strait hydrographic sections to remove baroclinic effects, which lead to an overestimate of the transport by up to 40% in summer. The conversion factor from SLD to the transport is estimated as Λ = (10.2 ¿ 1.1) ¿ 106 m2 s-1 with a reference value of SLD, Δη0 = 197 ¿ 3 cm. Therefore, SLD provides a means to investigate long-term variations of the transport through the Korea Strait and their relation to changes in the Pacific Ocean, such as El Ni¿o and decadal climate variations.