The joint training exercise on Gotland Island began on Wednesday and was aimed at establishing “a comprehensive defense of the island” on sea and land.

Historically neutral Nordic nation Sweden joined NATO in March 2024, becoming the alliance’s 32nd member and significantly increasing NATO’s capabilities. In addition to providing a sophisticated and well-equipped military, which is specialized for operations in the Nordic and Baltic regions, it is noted for its small yet effective fleet of diesel-electric submarines, which were designed for the unique shallow waters of the Baltic Sea.

Sweden also brought to NATO something that could be crucial in a war with Russia: the heavily fortified island of Gotland. Since the Iron Age, that small island has been seen as a strategic location, leading to the construction of towns, a hillfort, and even Visborg Castle.

There has been a more or less continuous military presence on the island for the last 200 years. In the 19th century, the first modern fortifications were built, followed by a series of improved defensive positions through the Cold War. Although the military capabilities were downgraded in the 1990s and early 2000s amid the end of the Cold War, Stockholm has again begun to invest in the island’s military infrastructure.

“It’s basically like a huge aircraft carrier in the middle of the Baltic,” Quartermaster Oscar Hannus of the Swedish Navy told the Kyiv Post as Swedish and Polish military officers prepared for a recent Operation Gotland Sentry exercise.

The joint training exercise began on Wednesday and was aimed at establishing “a comprehensive defense of the island,” on sea and land, the Swedish military explained in a post on social media.

The drills involved more than 100 Polish paratroopers from the 6th Airborne Brigade, who carried out drops to secure key points on the island before additional forces arrived. It was described as “the largest deployment of airborne forces and resources in the history of Poland and Sweden’s cooperation.” 

Why Gotland Matters

Gotland, located 50 miles from the mainland of Sweden and approximately 160 miles from the Russian exclave of Kaliningrad, is home to around 60,000 people, mostly civilians. It has been under Stockholm’s indirect control since the ninth century, but Sweden officially gained the island as part of the Treaty of Brömsebro in 1645, signed towards the end of the 30 Years’ War.

As Gotland is also located between Sweden and Latvia, it has been seen as a potential target should Moscow decide to move into the Baltic states. During the Cold War, as many as 25,000 soldiers in four regiments were based on the island, and although current numbers aren’t close to those levels, Sweden has sought to bolster its presence accordingly. In 2018, Stockholm reactivated the Gotland Regiment, which can trace its origins back to the 19th century and is now responsible for the island’s defense.

Past training has included British paratrooper operations in May near Visby, the island’s largest city and site of the former fortress, while this past summer, the US military conducted HIMARS rocket testing.

These drills are meant to address concerns that Russia could seek to carry out an amphibious invasion in the early stages of a conflict with NATO to gain control of the “unsinkable aircraft carrier,” which is why the recent training exercises to defend Gotland were being conducted.

The exercises also come six months after Swedish authorities carried out an investigation into the suspected sabotage of a water pump that provided drinking water to residents and military personnel on Gotland. There has been speculation that the region’s increased acts of sabotage, which included the cutting of the 728-mile-long undersea C-Lion 1 fiber optic cable between Finland and Germany, are part of an ongoing Russian hybrid warfare campaign.