In the Baltic Sea, over a thousand mines blocked the waterways leading from Tallinn to Kronstadt years ago. Several hundred mines blocked the entire basin around Ukrainian ports in the Black Sea a few years ago. Ukrainian drone attacks forced tankers carrying Russian oil to change their carriers and navigate the Black Sea through waterways running through Turkish territorial waters. Iran, using drones and missiles, blocked the Strait of Hormuz. Houthi missile and drone attacks have reduced shipping traffic through the Suez Canal by almost 80%.

Narrow passages may not necessarily be blocked by direct military operations or pirate activity. It could be a sabotage in the form of an apparently damaged ship blocking the waterway. Disruptions to ship passages and port approaches can be caused by an oil spill or a drifting tanker. We observed the latter in the Mediterranean.

International sea-land supply chains are already more flexible than before the Covid-19 pandemic. However, any modification to logistics on sea routes often results in changes in land logistics. Blockages and bottlenecks on sea routes cause significant changes in the planning of production processes and deliveries to the consumer market.

Most waters critical for sea transport can be avoided. Alternative routes are now planned with the support of satellite technologies and artificial intelligence. However, any change in the flow of sea freight transport is associated with changes in delivery times and transport costs. The ton-mile transported often comes at a high cost.

Even route optimization using IT tools will not change the fact that increased consumption of more expensive fuel comes at a cost. Extending a vessel’s route from the port of shipment to the port of destination also extends delivery times. And time is money. Alternative solutions may prove ineffective in a situation of acute conflict.

Crude Oil Supply Threat Points. Source: U.S. Energy Information and Administration (EIA)

Studies indicate that there are seven water areas globally whose closure could disrupt logistics along maritime supply routes. Today, we know that the Strait of Hormuz is a passage of strategic importance due to the supply of crude oil to many Asian countries. A critical area on this route is the Strait of Malacca, which connects the Indian Ocean with the Pacific Ocean.

The Cape of Good Hope is also considered a strategic point. The routes around the Cape are not a bottleneck. The passages around southern Africa are a vital trade route and an alternative route between Asia, Australia, Europe, North America, and Latin America. This route is currently heavily used in both directions due to the threat of Houthi attacks in the Red Sea.

Seven Hotspots and More

Experts from the U.S. Energy Information and Administration (EIA) have identified seven chokepoints crucial to the unimpeded transport of crude oil through maritime routes. These are essentially waters located on major trade routes, the capacity of which determines the efficiency of global maritime oil transport. Among them is the Bab al-Mandab Strait (“Gate of Tears”), which connects the Red Sea with the Gulf of Aden. Located between Djibouti and Yemen, it is a water body under attack by the Houthis. Bab al-Mandab is approximately 26 km wide at its narrowest point.

In its special report “World Oil Transit Chokepoints,” the EIA also lists the Bosphorus, the Dardanelles, and the Suez Canal in the Mediterranean as critical maritime passages. For American maritime trade, the Panama Canal and its adjacent ports are a critical strategic passage. In the North Sea, only the Danish Straits are singled out. The passage between the Atlantic and the Mediterranean near Gibraltar should also be added.

The Baltic Sea also has its critical chokepoints. Separated from the North Sea by the Danish Straits, it has narrowing points that, in the event of a more or less overt conflict, could be vulnerable to military action. Both the Gulf of Finland and the Gulf of Bothnia could be blocked. In Poland’s case, actions resulting from blocking the entrance to the Gulf of Gdańsk, as well as to Świnoujście and Szczecin, should be anticipated. And these threats cannot be treated hypothetically.

Straits and Canals

The Strait of Malacca is an important route not only for the transport of oil and LNG. It is also the main passage connecting the markets of Europe, the Middle East, and India with the countries of Asia and Oceania, as well as Australia and New Zealand. These waters are vulnerable to piracy attacks. Over 23 million barrels of oil are transported daily through the routes connected by the Strait of Malacca. This represents 29% of global seaborne oil supplies, according to American analysts.

Crude oil accounts for over 70% of energy supplies, with refined products accounting for the remainder of tanker transport, according to the EIA. If the Strait of Malacca is blocked, passages through the Sunda Strait and Lombok Strait could be used. An alternative route is to circumnavigate the entire archipelago.

The impact of the Strait of Hormuz blockade on maritime trade. Source: UNCTAD, Graphics: TrasportoEuropa.it

The Strait of Hormuz connects the Persian Gulf with the Gulf of Oman and the Arabian Sea. The largest tankers, bulk carriers, and container ships can pass through it. Its blockage means that only a portion of oil, gas, and products can be transferred via pipelines to the international market. Up to 21 million barrels per day enter the Persian Gulf. This means that 20% of global demand is met through this region. Countries using ports in the Persian Gulf and Oman are also important players in the grain, fertilizer, and industrial and consumer goods markets.

The Suez Canal and the Bab el-Mandab Strait are strategic maritime transport routes connecting the Asian market with European countries, as well as Asian countries in the Black Sea region. Combined oil transport through these routes accounted for approximately 6% of global seaborne supplies. The Houthi attacks and the blockade of shipping through the Red Sea proved extremely disruptive to global logistics networks. However, operators proved flexible and quickly adjusted their supply routes.

It turned out that, on a global scale, longer and more expensive routes around the Cape of Good Hope, which bypass both the Bab el-Mandab Strait and the Suez Canal, were feasible. The Northern Sea Route proved unattractive and inaccessible for mass commercial shipping, both with crude oil and general cargo.

In Northern Europe, the Kiel Canal is a strategically important link. It is used for general cargo, the passage of smaller bulk carriers, and the transit of crude oil. However, small tankers can pass through it. Therefore, this route is mainly used by product carriers.

The EIA reports that “200,000 barrels per day of petroleum products were transported through the canal in the first half of 2025.” Russia was once the largest source of refined product transport through this route. Since 2022, transfer activity from Russia has declined. The Netherlands, Belgium, and Denmark are using the Kiel Canal more actively for maritime product transport.

Around 330 commercial vessels pass through Gibraltar daily to the Mediterranean and back to the Atlantic. Over 90,000 ships, including bulk carriers, tankers and container ships, ferries, and other roll-on/roll-off vessels, make these crossings annually. Passenger ship traffic is strong in this area. Oil flows from European Russian ports to Turkey via this route. Russian and Turkish ships carrying oil and products from the Black Sea to African and European ports also pass through Gibraltar.

Energy Suppliers to the EU. Source: EUROSTAT

For over 100 years, the Panama Canal has connected the Pacific Ocean with the Caribbean Sea and the Atlantic Ocean. “In fiscal year 2025 (October 1, 2024 to September 30, 2025), over 2.3 million barrels of crude oil and other liquid cargoes were transported through the canal daily, the majority of which (approximately 2.2 million barrels) were refined petroleum products,” according to the EIA. However, it is also a waterway of strategic importance for trade in industrial and consumer goods.

In fiscal year 2025, only 3% of total global trade in crude oil and products passed through the Panama Canal. It is also a crucial route for LNG supplies from gas terminals in the Gulf of Mexico to western South America and Asia. An alternative to the Panama Canal is to pass through the Strait of Magellan around Cape Horn. However, sailing around South America costs a ship an additional 10,000 nautical miles.

Alert for the Baltic

Observations of local conflicts show that there is always a potential risk that a crisis in one region could spill over into another. Today, we have such a situation in the Baltic Sea. It began with infrastructure damage. Today, the consequences of the conflict in the Black Sea have affected Russia’s seaports. But not only that. Disruptions of satellite signals in the Baltic Sea are almost daily occurrences, ranging from signal disruption to physical damage to a ship in a frequently used passage nearby.

The Danish Straits are passages connecting the Baltic Sea with the North Sea, strategically important for all countries in the region. For Russia, they are a route for exporting crude oil and importing industrial and consumer goods. For Poland, they are the only supply route for crude oil, refinery products, and LNG. They are also a crucial route connecting Polish exporters and importers of industrial and consumer goods. Mining the Danish Straits would practically exclude the Baltic from trade with the world.

Potential hotspots and blockages in the Baltic Sea. Screenshot: SATBAŁTYK, IO PAN. satbaltyk.iopan.pl, Prepared by: Marek Grzybowski

The EIA estimates that tankers transport approximately 4.9 million barrels of crude oil and products daily through the Danish Straits. This represents 6% of global trade, a similar share to the Suez Canal. The EIA notes that “This volume is almost 60% higher than in 2021 due to the shift in trade flows from Russia.”

It is significant that a large portion of crude oil and products is transported by shadow or zombie ships. Since these are usually old and not always operational, this poses a threat to the routes leading from Russian fuel terminals to the North Sea. Specifically, shipments were destined for refineries in Asia and Turkey, not Western Europe.

The Gulf of Finland plays a significant role on this route. Russia sends its largest oil shipments through this bay, where ships of the gray fleet dock. The Ukrainian Ministry of Defense reported a successful attack on installations in Primorsk and Ust Luga, as well as a shipyard in Vyborg, where the icebreaker Purga (Project 23550) was damaged. The Ukrainian Ministry of Defense justified the destruction by stating that “It is not just an icebreaker, but a hybrid warship. It is armed with artillery and can carry Kalibr or Uran containerized missile systems. It was intended for the Coast Guard of the Border Service of the FSB.”

Russian oil exports surged in early 2026. In the first half of March, Russia shipped approximately 4 million barrels of crude oil per day by sea. This was the highest level of oil supply since the end of 2025. Weekly revenues from oil sales provided suppliers with $2.46 billion, the highest since March 2022, according to Bloomberg.

Oil flowed on shadow fleet vessels and tankers operated by operators from around the world, including European shipowners. According to Reuters, the partial destruction of the installations reduced oil exports from Baltic terminals by 60% of Russia’s total crude oil exports. Estimates include both seaborne and pipeline exports, which amount to approximately 2 million barrels per day.

So far in 2026, Ukraine’s armed forces have attacked 13 infrastructure facilities related to oil and gas export and processing in Russia. The Ukrainian Ministry of Defense states: “Thus, the Baltic Sea region has shifted from a ‘safe haven’ to a high-risk zone for Russia. The systematic destruction of oil infrastructure through deep strikes depletes the enemy’s resources and creates long-term obstacles to rebuilding its military potential.” The war from the Black Sea has effectively spilled over into the Baltic Sea.