November 13, 2026

We tracked a ship in North Korea’s shadow fleet. This is how it stays in the dark

It’s the middle of the night in April 2023 in the East China Sea. A North Korean-linked oil tanker, sailing under different country’s flag, suddenly goes dark. It stops transmitting its location using the Automatic Identification System (AIS) machine that all larger commercial ships have on board. To the casual observer looking at a computer screen, it ceases to exist. Ten days later, the ship reappears on the screen. Its AIS signal shows it is off the coast of southern China.

But the ship itself had never left its original location. We know because we spotted it by satellite.

It’s called New Konk and it was preparing for a voyage to deliver sanctioned oil. This is just one of hundreds of ships in the North Korean shadow fleet that keeps the pariah state’s economy afloat in the face of international sanctions.

North Korea isn’t the only country with a shadow fleet. Russia has also amassed hundreds of dark ships to evade sanctions following its invasion of Ukraine in 2022. And Iran is using its shadow fleet to dodge the US blockade on its ports. But North Korea is the pioneer of this murky world. The hermit state launched its dark fleet more than a decade ago in response to UN sanctions over its nuclear weapons and missile programs. Now, its fleet is believed to include up to 750 vessels, though the exact figure will never be known.

One of us (Justin Hastings) has been tracking North Korea’s sanction evasion efforts, including its shadow fleets, for more than a decade. In a partnership between the University of Sydney and the National University of Singapore’s Centre of Maritime Studies, the three of us have also tracked the methods these ships use to obscure their identities and create new methods to try to detect them at sea. This is the story of one ship in North Korea’s fleet, the New Konk.

A shadow ship is born

Before New Konk became, well, New Konk, it was just an ordinary cargo vessel. It was built in 1991 in Japan and operated by South Korean firms, doing unremarkable shipping runs around the world. But by 2019, it had gone dark. The ship was photographed at sea transferring oil to another ship called the Vifine.

The transaction raised alarm bells at the Panel of Experts of the United Nations committee on North Korean sanctions. Ships that are banned from entering ports because of sanctions often transfer goods at sea, in secret. New Konk and Vifine were both owned by firms that shared the same address in Hong Kong and were registered the same month. This was no coincidence. As UN inspectors tracked the ship, New Konk started regularly taking oil from supply ships at sea and that oil would ultimately end up in North Korean ports.

Hiding in plain sight

Hiding from sanction enforcers is serious business. So New Konk begins its disappearing act. Generally, ships sailing in international waters are required to have two identification numbers. One is its International Maritime Organisation number, which stays with the ship throughout its life. It has to be permanently visible on the ship’s hull. But it can be painted over by owners trying to hide the ship’s identity. The second is what’s called a Maritime Mobile Service Identity (MMSI) number. It’s sort of like a unique phone number issued by a ship’s flag country when a vessel is licensed. Like a phone number, it can change when a ship’s owner changes.

Every ship uses these numbers to broadcast its identity to other ships and ports as it sails. In October 2019, New Konk stopped using its own IMO and MMSI numbers, and began adopting new identities. In 2020, for instance, when New Konk was sailing in the East China Sea, it transmitted an MMSI number belonging to another ship called the Mouson 328. The UN Panel of Experts used satellite imagery to pinpoint a ship with New Konk’s dimensions and shape broadcasting using Mouson 328’s identity in August 2020. The real Mouson 328, another ship in North Korea’s dark fleet, was somewhere else. It was registered under a new MMSI number, which left New Konk free to use its old one. It’s known in the shipping world as vessel identity laundering.

A fresh makeover

Broadcasting a fake MMSI doesn’t make a ship magically invisible. If a ship is pretending to be another vessel, it needs to look like the original too. In late 2020, New Konk pulled into the Fujian Yihe Shipyard in eastern China for a paint job. When it arrived, it had a red deck and when it departed, the deck was green. And with the paint job came a new name: F.Lonline and another new MMSI.

A long, strange voyage

Remember when the New Konk went dark in the East China Sea in 2023? It wasn’t the first time it did this. It’s called “spoofing,” when a ship hides its true location, speed, and destination from monitoring systems. Sometimes the crew will broadcast fake GPS data to make a ship appear to be somewhere else entirely. It’s a dead giveaway when oil tankers “sail” over land.

In early April, the ship was docked in Sansha Bay near Ningde, China. It’s a common staging area for North Korean shadow fleet ships before their voyages. It then sails north through the Yellow Sea to the North Korean coast. On July 3, under the cover of darkness, it’s photographed transferring oil to another ship, which then delivers it to an oil terminal in Nampo, North Korea.

[A] second map shows the journey broadcast from its AIS machine, using fraudulent MMSI numbers and names. We watched the trickery from March to July 2023. [There were] … the random lines and breaks in the paths – that’s the ship turning off its tracking or faking its location. [On] this fake journey… the ship [sailed] east into the East China Sea in early Aprils, then south into the Taiwan Strait, then jump[ed] to the South China Sea and then bizarrely back into the East China Sea. 

According to its fake identities, it loiters in the Yellow Sea between China and the Korean peninsula for about a week before finally disappearing on the same day the oil transfer took place.

When the ship’s signal reappears shortly after the transfer, it claimed to be in the middle of the Yellow Sea.

New Konk’s last sighting

And this is where we lose its trail. By 2023, New Konk was already an ancient ship. In the back half of the year, we know it broke down and was moored in North Korean waters waiting for repairs. We don’t know if it was ever able to sail again. Most of North Korea’s shadow ships are so old and poorly maintained they eventually fade away. The only trace they ever existed is an AIS identity. The last AIS location broadcast for New Konk was in June 2025 in the South China Sea. But it was almost certainly not our ship, it was likely another ship spoofing, using its IMO number and a fraudulent MMSI.

Targeting a shadowy industry

Cracking down on shadow fleets is as difficult as tracking them. The companies buying and selling goods to North Korea can be targeted by the UN. The challenge is identifying the true culprits or the countries behind them. It’s also politically fraught. China can block any UN sanctions on Chinese companies with its permanent seat on the Security Council. Indian and Chinese companies are the primary buyers of Russian oil, and sanctioning them would risk worsening tensions with both countries.

Under UN sanctions, states are required to stop North Korean ships from conducting oil transfers in their exclusive economic zones, but China often turns a blind eye to this. Countries are also legally obligated to stop North Korean shadow fleet ships from docking in their shipyards or ports. But identity laundering offers plausible deniability. Some countries have resorted to force. US military vessels have stopped and boarded Russian-linked ships transporting oil from Venezuela. European and British naval vessels have recently done the same.

The reality is no country can police the world’s oceans by itself.

We’re trying to make it a bit easier though. We’re building a database of these ships’ movements on a supercomputer and using machine learning to detect patterns that could indicate when vessels are in a suspected shadow fleet. It’s a giant game of cat-and-mouse, with North Korea, Russia and others devising increasingly sophisticated ways to hide their ships, daring other nations to stop them. 

The enforcers will always be a step behind.

Find out more about the authors:

Read / watch the original story!

Interact with the original interactive story at The Conversation!

https://doi.org/10.64628/AA.9qvewyq4v

This article is republished from The Conversation under a Creative Commons license.

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