Gotland is a long, low slab of limestone sitting almost exactly in the middle of the Baltic Sea. It has a few tens of thousands of residents, a walled medieval town at Visby, and a strategic value out of all proportion to either.

This week, Germany and Sweden have been rehearsing what it would take to reinforce it in a hurry. Exercise Silver Wotan, running from 14 to 23 September 2026, is the first joint German-Swedish rehearsal of the rapid-reinforcement plans for the island. On Friday the exercise reached its surge phase, with German troops and vehicles coming ashore at Visby and Luftwaffe aircraft working overhead.

The scenario is deliberately specific: Sweden asks NATO for help, and German air force and navy personnel arrive to help deploy and protect Sweden's land-based anti-ship missile systems.

Why Gotland

Look at a Baltic chart and the argument makes itself. Gotland sits roughly halfway between the Swedish mainland and the Baltic states, athwart the approaches to the Gulf of Finland and inside comfortable reach of Kaliningrad. Whoever holds it can watch, and potentially contest, a large share of the sea.

Eight NATO members now border the Baltic: the three Baltic states plus Denmark, Germany, Finland, Poland and Sweden. Sweden's accession in March 2024 turned the island from a national responsibility into an alliance one.

The permanent garrison is the Gotland Regiment, P 18, Sweden's youngest and smallest, rebuilt as Stockholm re-militarised the island. It is the structure into which any arriving allied force has to slot, which is precisely the problem Silver Wotan is designed to stress.

The Air Component

The aviation side of this exercise is less visible than the landing craft, and arguably more important. Getting a reinforcing force to an island is an airlift and air-protection problem as much as a naval one.

Publicly available flight-tracking data showed Luftwaffe transport aircraft working the operation, including at least one A400M Atlas. Visby's commercial airport has long doubled as a military field for exactly this sort of activity, which is convenient and also, in a contested scenario, a single point of failure worth thinking hard about.

Overhead, the Luftwaffe committed Tornado di Panavia aircraft to the surveillance task. The Tornado is late in its German career and close to replacement, and there is something pointed about the type spending part of its last years flying reconnaissance over the Baltic rather than the North German Plain it was designed for.

Friday: The Surge

The Swedish Armed Forces announced the main move themselves.

Equipment moved by sea to Visby, including aboard a commercial roll-on roll-off ferry — an unglamorous detail that says a great deal about how European reinforcement actually works. There are not enough grey hulls to move an army. There are, however, a great many car ferries.

At the harbour, German and Swedish personnel secured the port and ran the reception of the arriving force — the deeply unheroic business of getting vehicles off a ramp, through a gate and onto a road without a queue forming. Swedish CB90 fast assault craft, a type German troops are also trained to operate, worked the seaward side.

Among the equipment coming ashore were air defence systems. Swedish forces, meanwhile, operated the coastal anti-ship missile batteries that the whole scenario is built around protecting.

Not About Any One Thing

Swedish authorities have been careful to say Silver Wotan was planned well in advance and is not a response to any specific imminent threat. Sollfrank made the same point, and then extended it.

That said, the backdrop is not neutral. Sollfrank noted that hybrid activity has become a permanent feature of the threat picture rather than an occasional event, citing cyber attacks, sabotage, espionage and disinformation, and referring to recent disruption at German airports. He also said that since NATO's Baltic Sentry mission began, activity against critical underwater infrastructure in the Baltic has decreased.

Silver Wotan builds on Aurora 26 earlier this year, in which more than 18,000 troops from 13 countries exercised across Sweden, including a deployment to Gotland. What is new here is the concentration: two countries, one island, one problem, worked end to end.

The lesson underneath it is the one European planners keep arriving at. Deterrence in the Baltic is not mainly about which fighter you own. It is about whether you can get five hundred soldiers, their vehicles and an air defence battery onto a limestone island in the middle of the sea before anyone else decides the question for you.

Sources: Bundeswehr, interview with Lieutenant General Alexander Sollfrank by Simona Boyer, 17 September 2026; Swedish Armed Forces (Försvarsmakten); The War Zone; Swedish Armed Forces Gotland Regiment; NATO Allied Command.