According to maritime consultancy Windward, many more Russian-flagged vessels switched flags to other nations in March, re-registering to countries such as the Marshall Islands and St. Kitts to avoid getting itself into sanctions over the invasion of Ukraine.

During March, 18 ships, including 11 cargo vessels from the same fleet, changed their Russian flag to a foreign country, more than three times the monthly average of Russian ships, according to Windward's statistics. Based on statistics dating back to January 2020, it's also the first time the figure has surpassed double digits.

The flag of a vessel in the shipping sector indicates the country in which it is registered, which then has legal control over the ship. In truth, the flag of a vessel is almost always distinct from the nationality of the company that owns it. According to the BBC, around three-quarters of ships are registered in a jurisdiction other than where they are owned.

Eleven Russian ships that changed flags in March did so in the Marshall Islands, a country with an "open registry" that allows vessels to be registered regardless of their provenance. The common cost-cutting loophole known as the "flag of convenience" was previously discussed by Insider.

Due to the Russia-Ukraine conflict, which began in late February, the United States, the United Kingdom, and other allies have escalated sanctions against Russia. On March 8, US President Joe Biden signed an executive order prohibiting Russia from importing oil and gas, and Britain has stated that it would phase out oil imports by the end of the year. Several other countries have also made it illegal for Russian ships to access their ports.

From small multimillion-dollar yachts to big oil tankers, Russian ships are already in difficulty. The identification and location transmission system AIS, which should be turned on at all times at sea, has also been disabled, as this is how to escape detection but poses a risk to maritime security.

Gur Sender, Windward's product manager, said foreign companies have different motivations for de-flagging Russian vessels, ranging from wanting their ships to be able to operate around the world without restrictions to ethical reasons.

Reflagging is not always counterintuitive. Sometimes due to changes in ownership or operating areas, Sender said, adding that the average monthly number of flag changes in 2021 is 17 for Singapore and five for Japan this year. Still, they are both at a stable level with no major fluctuations.

If the war in Ukraine continues, Ian Ralby, CEO of I.R. Consilium, a maritime law and security consultancy, believes the practice will become more prevalent. Ships flying the flags of the Marshall Islands and St. Kitts & Nevis in the Caribbean are less likely to attract attention.