Iran secured relief from some international sanctions in exchange for agreeing in November to curb some of its nuclear research activity. The U.S. government said oil restrictions remain in place, though Iranian customers can secure relief from sanctions if they show a decline in crude oil purchases.
South Korea secured a six-month extension to the sanctions waiver in November.
Data published Tuesday by the state-run Korea National Oil Corp. show imports of Iranian crude oil doubled last month when compared with February 2013.
Year-on-year, South Korean imports of Iranian crude declined in January by 66 percent and by 34 percent in December.
Iran has touted its investment potential since brokering an interim nuclear deal with Western powers in November. Representatives from French energy company Total were among delegates who visited Tehran in early February as part of a French trade mission.