Baltic Icebreaking Season Ends

The last Finnish icebreaker returned to port on May 6th, ending what was in some places a very challenging ice season.

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The Finnish icebreaker Otso returned to her summer berth in Helsinki on May 6th, 2026, ending Finland’s 2025-2026 icebreaking season.

Notably, this season required all ten of Finland’s icebreakers. This includes eight operated by the state-owned company Arctia and two icebreaking tugs chartered from Alfons Håkans.

I noted in a 2024 article that all of Finland’s icebreakers are typically required about 1-2 times per decade. That statement doesn’t seem to be holding, as all ten were also required in the 2023-2024 cycle. In other words, all of Finland’s icebreakers were required in two of the last three icebreaking seasons.

By ice coverage, this winter was average¹ with the peak of 181,000 km²:

Here is a short (less than one minute) video that Arctia published about this year’s season:

Those of you who follow the subject closely might be surprised by the number of vessels assisted and the number of tows required compared to 2023-2024, which had only a 135,000 km² peak.

The Finnish Transport Infrastructure Agency (Väylä) explains (translated via Microsoft Edge from the original):

… the extent of the ice cover as an indicator does not tell us how difficult the conditions have been for merchant shipping.

Often, the strong winds of mild winters pose greater challenges than winters with extensive ice cover, during which long periods of frost occur. This was also the case this past winter. Ice development was slow but steady from early winter to mid-March, thanks to prolonged periods of windless frost in all sea areas. Therefore, the situation was stable for a long time in terms of traffic and icebreaking.

The mild periods after mid-March brought with them long-lasting strong winds between the south and the southwest, when the area of ice cover in the Bay of Bothnia almost halved in a few days. The ice field was under severe pressure for several weeks, and each merchant ship had to be escorted to the ports one by one. Icebreaking assistance had to be suspended several times for safety reasons.

At the same time, the situation in the Archipelago Sea, the Bothnian Sea and the southern Bay of Bothnia eased, and the capacity previously transferred to these areas could be moved further north.

You can see this in some of the data that I pulled from Väylä. For example, although the maximum ice extent was highest during this most recent season, the number of tows was similar to 2022-23, which had a much smaller maximum:

This is because although the full fleet of icebreakers were needed to open channels, the icebreaking conditions themselves were generally not as challenging.

Sweden’s Icebreaking Season

On May 5th, Sweden’s smallest icebreaker Ale concluded icebreaking operations, marking the end of the season.

According to the Swedish Maritime Administration, Swedish icebreakers assisted 979 vessels, compared to only 220 in the 2024-25 season. Sweden used all six of its icebreakers and two multi-purpose vessels.

Elsewhere in the Baltic

During my most recent Baltic Sea update several icebreakers were still operating in the Baltic Sea. Here is wrap-up of the end of their seasons:

Russia:

The Russian icebreaking season in the Gulf of Finland ended on April 14th. According to Rosmorport:

Since the beginning of January, 12 FSUE “Rosmorport” icebreakers have escorted more than 3.5 thousand vessels en route to and from the ports of the Baltic Sea. The flagship of the flotilla alone, the world’s largest non-nuclear icebreaker Viktor Chernomyrdin, has escorted 437 vessels since the beginning of winter navigation.

The most difficult situation was recorded on the approaches to the seaports of Primorsk and Ust-Luga, where there was a strong compression of ice, which complicated the work of icebreakers.

Safe navigation in 6 seaports of the Gulf of Finland during the period of icebreaker support in 2025–2026 was provided by the FSUE "Rosmorport" flotilla consisting of 6 linear icebreakers (Viktor Chernomyrdin, Vladivostok, Murmansk, Kapitan Sorokin, Mudyug, Kapitan Nikolaev) and 6 port vessels (Ivan Kruzenshtern, Semyon Dezhnev, Kapitan M. Izmailov, Kapitan Zarubin, Kapitan Kosolapov, Kapitan Plakhin).

If you comparing that list to Rosmorport’s original plan, you will note that Murmansk was added and Krasin, originally planned to take part in icebreaking, instead entered drydock.

As I mentioned in my earlier article, the Project 22220 nuclear-powered icebreaker Sibir provided additional capability in the Gulf of Finland during February and March.

Estonia:

Botnica returned to port on March 30th and EVA-316 on April 14th, ending Estonia’s icebreaking season. According to the Estonian Transport Administration:

“In total, icebreaking operations in the Gulf of Riga lasted 98 days, and in the Gulf of Finland slightly more than two months, or 65 days. During this time, 173 vessels required assistance from icebreakers – 115 in the Gulf of Riga and 58 in the Gulf of Finland,” explained Are Piel, Icebreaking Coordinator at the Transport Administration.

Piel pointed out that the icebreaking season was difficult, especially in the Gulf of Riga, which was frozen throughout its entire extent from Pärnu to the Irbe Strait.

“Ships became stuck in the ice already upon entering the Irbe Strait. In places, the ice thickness in Pärnu Bay reached 55 cm, and pressure ridges formed piles rising up to 1.5 meters above the water surface and extending a further 2 meters below. Such conditions required the regular formation and management of ship convoys, which in turn kept the volume and intensity of icebreaking operations high throughout the entire period,” Piel added, noting that constantly changing ice conditions required continuous replanning of activities.

Latvia:

The icebreaking season ended on April 8th, marked by a ceremony held onboard the icebreaker Varma.

Photo: LETA, Paula Čurkste

According to the Port of Riga:

The ice navigation season this year lasted 6 weeks, and icebreaker support was provided to 148 ships. By ensuring the continuity of the Riga Port operation, 100 million euros have been saved for the country’s economy.

This year’s ice navigation season in the Baltic Sea region was particularly challenging. The Gulf of Riga froze very rapidly, and the ice conditions were further aggravated by strong winds, which created drifting ice ridges up to 4 meters high. Previously, such severe weather conditions in the Baltic Sea were recorded 15 years ago – in the winter of 2011.

Thoughts and Comments:

Consistent cold temperatures early in the winter pushed this year’s peak sea ice to the highest recorded since the 2010-2011 season. This pushed the extend of the ice further to the South, requiring rare icebreaking operations in Germany and Latvia. (Latvia hadn’t used its icebreaker, Varma, since 2018).

In the Gulf of Finland, thick ice and ice compression created challenges for Russia, which had to bring in two additional icebreakers including the nuclear-powered Sibir. Russia will face icebreaking challenges in the future. As I noted earlier this year:

Russia is building powerful nuclear icebreakers, but it will also need to replace a large number of icebreakers that serve the Baltic Sea and other key regions. Of the twelve Russian icebreakers [planned for use in the Baltic], ten are more than forty years old, and eight of them were built at Helsinki Shipyard. This trend continues across much of Russia’s icebreaking fleet— many of the vessels are old and require replacing. Because of sanctions, Russia must now rely on its own shipyards, making this an even more difficult challenge.

In Finland and Sweden, it was a relatively easy icebreaking season. Despite the extent of the ice, the consistent cold meant that the ice was stable. In some areas, especially late in the season, it did melt and stack in ridges against the Finnish coast.

Icebreaker replacement programs are already underway in Finland, Sweden, and Estonia. As mentioned, Russia has plans but is facing challenges in replacing its fleet. Latvia might also be considering replacing Varma after this season. One thing is clear: the need for icebreakers is not going away anytime soon.

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All the Best,

PGR

PS: As I was about to publish this article, my friends at Railotech released their own summary of the Baltic Icebreaking season. Here is a key sentence from the article:

The 2025 – 2026 winter was not exceptional in terms of ice extent, but it pushed the icebreaking fleets across the Baltic Sea to their limits. Rapid ice formation, combined with wind-driven compression, resulted in full fleet deployment across multiple sea areas.

I agree with their analysis. But do click through to the article—it’s definitely worth a look, especially for the graphics depicting the order and timeline of icebreaker deployments, which were notably different in Finland this year. Railotech explains:

In a notable operational shift, the Finnish Transport Infrastructure Agency adjusted its deployment model to improve cost efficiency. Rather than dispatching its largest assets first, the season began with smaller icebreakers.

Now go and read the full article!

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Related articles from Sixty Degrees North:

• < 115,000 km²: mild season

• 115,000 km² ≥ average season > 230,000 km²

• 230,000 km² ≥ severe season > 345,000 km ²

• ≥ 345,000 km²: extremely severe season

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