Composite surface current velocity data (ADCP and GEK), coastal sea level data and hydrographic data were used to examine the seasonal variations of upper-ocean flow around the Soya Warm Current (SWC) region. We've discovered that the subsurface counter-flow (northwestward current) along the offshore side of SWC (coastal trapped southeastward current) transiently occurs in spring, i.e., the timing of dramatic exchange from East Sakhalin Current Water (ESCW) to SWC Water (SWCW). In winter, cold and fresh ESC water reached near Hokkaido coast and had the bottom-intensified/controlled flow structure. Then, it gradually accumulated on the shallower side of the shelf area off Hokkaido. In spring, the prevailing northwesterly wind was weakened and the flow energy of wind-driven ESC rapidly decreased. As a result, the modified ESCW (slightly warmer and saltier water) remained on the shelf area and its flow structure changed to the surface intensified density current, i.e., the northwestward counter-flow off the SWC. Our model simulation, which is forced by the temporal change in ESC and SWC volume transports from late winter to early-summer, suggests that such counter-flow is formed as a part of the clockwise baroclinic circulation on the shelf area.