Almost two years after its launch, North Korea’s first ballistic missile submarine, the No. 841 Hero Kim Kun Ok, has yet to enter operational service.
Satellite imagery from May 2025 confirms that the vessel remains docked under a security canopy at the Sinpo South Shipyard, with no visible signs of deployment.
According to satellite analysis by Beyond Parallel and the Center for Strategic and International Studies (CSIS), the submarine has not put to sea for any extended period since its unveiling in September 2023.
The vessel was originally introduced during a ceremony attended by Kim Jong-un, who referred to it as a “standard type of tactical nuclear submarine” and a key component of North Korea’s evolving nuclear triad.
North Korea’s No. 841 “Hero Kim Kun Ok” submarine docked under canopy at Sinpo base, May 30, 2025. (Source: beyondparallel.csis.org)
The Hero Kim Kun Ok is believed to have been converted from a Type 003 attack submarine into a diesel-electric ballistic missile submarine (SSB). It is equipped with ten vertical launch tubes, potentially capable of firing both ballistic and cruise missiles.
This configuration aligns with North Korea’s stated intention to develop a platform capable of delivering nuclear weapons from sea.
Following its launch, the submarine spent approximately a year undergoing construction and outfitting inside a covered graving dock at the Sinpo Shipyard.
In December 2024, it was moved to the secure boat basin at Sinpo South, where it displaced the experimental 8.24 Yongung (August 24 Hero) ballistic missile submarine. Since then, only minimal activity has been observed in the area.
As of May 30, 2025, the Hero Kim Kun Ok remains under the same canopy, with the conning tower partially visible. A single unidentified object has been present beside the submarine for about five months. Analysts note no signs of recent activity in the immediate vicinity, and no supporting vessels or infrastructure appear to be in use.
Despite official statements portraying the vessel as a critical deterrent asset, its lack of operational status suggests unresolved issues. If the conversion proves successful, its first sea trials could begin within 6 to 12 months. However, full blue-water capability, if achievable, would likely take years.
The submarine may also serve as a test platform for future technologies, including missile systems or potentially a nuclear propulsion unit. Kim Jong-un has publicly outlined ambitions to modernize the navy by converting medium-sized submarines into attack platforms and developing nuclear-powered vessels.
Meanwhile, satellite imagery also shows the 8.24 Yongung submarine docked nearby, with three unidentified objects positioned on its deck.
One of these appears to be cylindrical and may relate to maintenance work or an early prototype of a dry deck shelter or rescue chamber. North Korea has lacked dedicated submarine rescue capabilities since decommissioning its sole Kowan-class rescue vessel.
While the operational timeline for the Hero Kim Kun Ok remains unclear, North Korea may choose to conduct a symbolic submerged missile launch before the end of 2025.
Earlier in May, a newly launched North Korean destroyer suffered a dramatic launch failure at the Hambuk Shipyard in Chongjin, capsizing as its stern slid into the water while the bow remained stuck on land.
Satellite images captured the vessel lying on its side, covered in blue tarps, with little visible repair activity. Despite structural completion, the warship never made it to sea, and was later relocated to Rajin, a port near the Russian border, raising speculation about Moscow’s quiet involvement in the recovery effort.
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