The order for an FSRU comes from Maran Tankers Management - a unit of Greece's largest shipper, Angelicoussis Shipping Group, MANA correspondent reported.
The deal also includes the option of building two LNG tankers with an additional order possible for next year, reports local news agency Yonhap.
DSME has delivered 89 ships to the Greek company and its affiliates since 1994.
Hyundai Heavy Industries, Samsung Heavy Industries and DSME have all been under heavy financial pressure given the challenging conditions in the container, bulk and offshore sectors. All have come up with government-sponsored restructuring plans, and have announced thousands of layoffs in an attempt to reduce overhead.