Following its August 2016 SLBM test and a September 2016 nuclear test by North Korea, evidence indicates that Pyongyang has started construction of a new ballistic missile submarine. Commercial satellite imagery shows heightened activity around the Sinpo South Shipyard, where the majority of North Korea’s submarines have been built. The shipyard recently underwent a revitalization program and the movement of raw and finished materiel and construction equipment into the area indicates that the shipyard is preparing for new building activity. The shipyard also has a circular component that appears to be intended either to aid construction of a new submarine or to be used as part of new vessel’s pressure hull. If the latter, the component, at 10-meters in diameter, would indicate construction of a submarine larger than North Korea’s sole Gorae- or Sinpo-class experimental ballistic missile submarine.