The Danish straits have become one of the most strategically important maritime chokepoints in Europe. What passes through Øresund, the Great Belt (Storebælt) and the wider sea space around Denmark does not concern Copenhagen alone. It affects Baltic Sea access, North Sea trade, energy supplies for northern Europe and, increasingly, the wider security debate that links the Baltic to the Arctic and the North Atlantic.
The comparison with the Strait of Hormuz is not exact. Denmark does not sit astride a single narrow passage in the same way Iran and Oman do in the Gulf. But the analogy captures something real. In geopolitical terms, Denmark has become a maritime hinge: a state whose geography makes it central to the circulation of oil, the movement of commercial shipping and the military balance of northern Europe.
A maritime gate between the Baltic Sea and the North Sea
The strategic value of Denmark starts with geography. The Danish straits are the main maritime gateway between the Baltic Sea and the North Sea, and therefore between Baltic ports and the Atlantic economy. Any ship sailing to or from Sweden, Finland, Poland, the Baltic states, parts of Germany and Denmark itself must take this geography into account.
This matters for civilian trade, but it also matters for strategy. For decades, control and monitoring of the entrance to the Baltic was a classic question of European security. That logic has returned with force since Russia’s full-scale invasion of Ukraine. Today, access to the western Baltic is no longer a secondary regional issue. It is part of the broader debate about energy resilience, critical infrastructure, naval mobility and deterrence in northern Europe.
There is also an important nuance. Denmark’s location gives it strategic weight, but not unlimited freedom of action. These are straits used for international navigation, not a national canal that can simply be shut at will. That makes Denmark less a sovereign valve than a gatekeeper under international law: indispensable because of geography, but constrained by the legal regime governing passage.
Oil traffic through Øresund and Storebælt surged after 2022
What has made this geography newly visible is oil. According to the USA Energy Information Administration, around 4.9 million barrels per day of crude oil and petroleum products flowed through the Danish Straits in the first half of 2025. That made them one of the world’s busiest maritime oil chokepoints, on par with the Suez Canal system and behind only a handful of much larger global routes.
The increase is striking not only in absolute terms, but also in speed. Compared with 2021, oil flows through the Danish straits were almost 60% higher by the first half of 2025. In practical terms, a route that was already important for northern Europe has become a global artery.
The explanation lies largely in the reorganisation of trade after 2022. Before the war, a substantial share of Russian oil was sold to European buyers. After sanctions and embargoes reshaped the market, that trade was rerouted. Russian cargoes began travelling longer distances toward buyers such as India, while countries around the Baltic replaced Russian supplies with imports arriving from elsewhere. Both shifts increased traffic through Denmark’s waters.
This is one reason the Great Belt has become especially important. For larger tankers, it is the deeper western route into and out of the Baltic. Maritime guidance updated in 2026 underlined that large hydrocarbon carriers have used this deep-water route more intensively since 2022, confirming how directly the war in Ukraine has altered shipping patterns in northern Europe.
The Russian shadow fleet has raised the stakes for Denmark
The rise in traffic is not just an economic story. It is also a story about risk. Part of the oil moving through the region is carried by ships connected to Russia’s so-called shadow fleet: older vessels, often sailing under foreign flags and opaque ownership structures, used to keep oil exports moving despite sanctions.
For Denmark, this creates a double vulnerability. The first is environmental. A heavier flow of oil tankers in narrow and sensitive waters means a higher risk of collision, grounding or spill. The second is political and security-related. Ships linked to sanctions evasion are harder to monitor, harder to regulate and often associated with weaker insurance, older equipment and unclear accountability.
That concern is no longer abstract. In early 2026, Danish authorities and partner states around the Baltic and North Sea publicly warned about growing maritime safety risks in the region. The issue is not limited to one country’s coastline. A serious accident in or near the Danish straits would affect a wider northern European maritime system, from marine ecosystems to energy logistics.
NATO now sees the western Baltic as critical infrastructure terrain
The strategic role of Denmark has also changed because the Baltic is no longer viewed only as a shipping basin. It is now treated as an area where critical undersea infrastructure, hybrid threats and military signalling overlap.
After repeated incidents affecting cables and other infrastructure in the Baltic Sea, NATO launched Baltic Sentry in January 2025 to strengthen surveillance and protection in the region. Denmark’s own armed forces then increased monitoring in and around its waters, including the western Baltic and the Kattegat. Danish Defence has noted that the Great Belt, Øresund and the Kattegat are already among the most heavily trafficked maritime zones in the country, with 300,000 to 400,000 vessels of various sizes passing through Danish waters each year.
That figure helps explain why Denmark matters beyond its size. In a crisis, the state sitting at the entrance to the Baltic matters disproportionately. It matters for reinforcement routes, for maritime situational awareness and for the protection of cables, pipelines, ports and offshore energy infrastructure. Since Finland and Sweden joined NATO, the military geography of northern Europe has shifted sharply, but Denmark has not become less important. If anything, it has become more important because it connects the newly enlarged Nordic-Baltic defence space to the North Sea and the Atlantic.
Denmark’s Arctic role makes the chokepoint argument even broader
The final reason the Hormuz comparison resonates is that Denmark’s relevance does not end in the Baltic. Through Greenland and the Faroe Islands, the Kingdom of Denmark is also an Arctic and North Atlantic actor.
That does not mean the Danish straits are physically part of the Arctic route system. They are not. But in strategic terms, the same state that sits at the maritime entrance to the Baltic also belongs to the kingdom that is centrally located in the Arctic and has been increasing defence investments in the Arctic and North Atlantic. This gives Denmark a rare geopolitical profile inside Europe: it is simultaneously a Baltic gatekeeper, a North Sea transit state and an Arctic stakeholder.
That combination matters more now than it did a decade ago. The Baltic has become more militarised, the North Sea is increasingly tied to offshore energy and critical infrastructure, and the Arctic is gaining weight in defence planning and shipping debates. Denmark is not at the centre of all these theatres in the same way. But few European states sit at the junction of all three.
Why this matters for northern Europe
The phrase “the Nordic Strait of Hormuz” is deliberately provocative, but it points to a real structural shift. Denmark’s importance is no longer explained only by its role in Scandinavian politics or EU decision-making. It is explained by the fact that geography, war, sanctions and alliance politics have made its surrounding waters more central to the functioning of northern Europe.
For the Baltic countries and Finland, Denmark is part of the maritime doorway to the wider world. For Sweden and Germany, it is part of the regional logistics map. For NATO, it is a monitoring and access point. For the oil market, it has become a chokepoint of global significance. And for the Kingdom of Denmark itself, this new prominence brings responsibilities as much as opportunities.
That is why the Hormuz analogy matters. Not because Denmark can replicate the politics of the Gulf, but because northern Europe increasingly depends on what happens in and around the Danish straits. In a more fragmented and contested maritime order, Denmark’s geography has become a strategic fact that the rest of Europe can no longer treat as background.
