Distribution and migration of larval and juvenile sandfish Arctoscopus japonicus in the coastal waters off Gangwondo were determined monthly from samples collected by a rectangular bottom net in the coastal waters off Gangwondo from March to July, 2011. Fish were collected in abundance from the northern waters from March to June. The average total length (${pm}SD$) was $11.5{pm}1.6$ mm in March increased up to $53.5{pm}3.3$ mm in June. The size distribution of sandfish by depth suggested that the fish grew waters less than 50 m deep until June, before moving deeper waters of around 100 m.