Similar to the situation in the Strait of Hormuz and the Taiwan Strait, navigation through the Kerch Strait has been significantly impacted by geopolitical tensions. As discussed above,1 prior to Russia’s invasion of Ukraine in 2022, tensions over the passage rights in the Kerch Strait peaked already in November 2018 when the Russian Federation blocked the passage of three Ukrainian naval vessels, seized them and detained the crew. This incident was discussed in the context of the on-going arbitration proceedings between Ukraine and the Russian Federation. However, the Russian Federation restricts access from the Black Sea to the Sea of Azov not only in respect of foreign warships. Prior to its blockade of the Sea of Azov in 2022,2 the Russian Federation imposed years-long navigational restrictions on foreign commercial ships seeking to navigate through the Kerch Strait for heading to or returning from Ukrainian ports in the Sea of Azov.
10.1 The Significance of the Kerch Strait for Commerce
The Kerch Strait falls entirely within the limits of territorial sea and/or internal waters. It gives access to the Ukrainian ports of Berdyansk, Mariupol and Henichesk, and to the Russian ports of Rostov-on-Don, Taganrog, Temryuk and Yeysk on the coast of the Sea of Azov. The Sea of Azov, in turn, is connected with the Caspian Sea via the Don River, Volga-Don Canal and Volga River. The Kerch Strait is the only maritime route from the major ports on the coast of the Sea of Azov to the Black Sea and beyond.
The Kerch Strait has relatively heavy traffic, reaching 15.229 crossings in 2010 and 19.451 in 2017.3 As shown in Figure 3 below, these rates of crossings are comparable to those of, respectively, the Åland Strait (connecting the Gulf of Bothnia and the Baltic Sea) and the Great Belt (largest, but not busiest, among
Number of annual ship crossings in the Kerch Strait and the Baltic straits
Note: Figure is based on data collected via the maps and figures of helcom annual reports on shipping accidents in the Baltic Sea area from 2007 to 2014, available
10.2
The Kerch Strait meets the primary geographic and functional criteria of an international strait.8 Passage through the Kerch Strait is guaranteed under losc and the strait is used for international shipping, including often by ships registered in the EU,9 between two larger maritime areas and its width is less than 24 nm.
However, passage of non-Russian ships through the Kerch Strait has been impeded, particularly as of 2014 when the Russian Federation gained control over both coasts of the strait. In 2018, the Russian Federation repeatedly obstructed the passage of ships operated for commercial as well as non-commercial purposes. The United States condemned, in August 2018, the Russian Federation’s alleged harassment of international shipping, referring to Russia’s practice in delaying hundreds of commercial vessels in the course of the previous five months.10 Similarly, the European Parliament condemned, in its resolution of 25 October 2018, “the excessive stopping and inspection of commercial vessels, including both Ukrainian ships and those with flags of third-party states, including ships under flags of various EU Member States”.11 The European Parliament further condemned the infringement of navigational rights in Ukraine’s territorial waters and pointed out that “Russia is bound by international maritime law and the bilateral cooperation agreement with Ukraine not to hamper or impede transit passage through the Kerch Strait and the Sea of Azov”.12
The Russian Federation restricts navigation through the Kerch Strait via strict administrative practices as part of its vts. In practice, these measures result in delays for foreign ships, particularly those that are passing through
Waiting times for passing through the Kerch Strait for ships visiting the Ukrainian ports in the Sea of Azov
Note: Figure is based on data collected from the monitoring reports of the Black Sea News on the duration of artificial delays of vessels in the Kerch Strait from 2018 to 2021, available
A regulatory approval system of vessel movement is effective in the vts of the Kerch Strait coverage area. Vessels enter the vts of the Kerch Strait coverage area and leave it, approach toward to a pilot’s reception position or start moving in the zone upon receipt of a vts of the Kerch Strait operator’s permit.13
These restrictions on the navigation of foreign ships in the Sea of Azov appear not to be founded on any relevant decisions of the imo. The Russian Federation appears to refer to imo Resolution A.857(20)16 as the legal basis of the vts in the relevant maritime area, but that resolution only serves to describe the principles and general operational provisions for the operation of a vts.17 Notably, the resolution does refer to the possibility that a coastal State may exercise its discretionary right to establish and operate under a vts a system of traffic clearances or vts sailing plans or both in relation to priority of movements, allocation of space, mandatory reporting of movements in the vts area, routes to be followed, speed limits to be observed or other appropriate measures.18 However, the resolution does not refer to such possibility in relation to straits used for international navigation. Such requirements hamper international navigation in a strait and could only be lawful in an international strait if the measure was previously approved and adopted by the imo (see, inter alia, Article 41(4) of losc).
The iala’s vts Manual provides the coastal State’s right to require traffic clearances explicitly only in respect of Port vts, while distinguishing it from a Coastal vts.19 Clearance of ship movements is defined in the manual exclusively in relation to access to ports.20 Clearances may also be required if
Generally, a vts is established where a particular maritime area exhibits high traffic density.24 Notably, such a vts or authorisation-based system has not been used in respect of Baltic straits that have a similar rate of annual crossings to that of the Kerch Strait, i.e. the Irbe Strait between Estonia and Latvia leading to the Gulf of Riga and the Åland Strait between Finland and Sweden.25 There appears to be no imo resolution which would permit the establishment of a vts specifically in the Kerch Strait and, therefore, the above-referred vts requirements would be unlawful if the Kerch Strait constitutes an international strait.26 Even though a port State can, by virtue of the principle of sovereignty, regulate access to its ports located on the coasts of the Sea of Azov, this would not entitle it to restrict access to the Ukrainian eez in the Sea of Azov (the existence of which is, however, contested by the Russian Federation), against the terms of the right of transit passage or to the ports of the other coastal State of the Sea of Azov against bilateral agreements between the coastal States on this matter, as argued above (see Chapter 4 of Part 2).
From the perspective of commerce and international relations, it is important to have legal certainty regarding the rules regulating maritime navigation. The interrelationship of a coastal State’s potential claim to internal waters in a densely navigated maritime area on the one hand and, on the other hand, the imposition of discriminatory navigational restrictions is illustrated by the Vironia incident in the Russian Federation’s maritime area in the Gulf of Finland, as discussed next.
Supra Chapters 4–5 of Part 2.
Supra Chapter 4.8.2 of Part 2.
Ibid.
Ibid.
Ibid.
Ibid.
European Parliament resolution (EU) No 2018/2870(rsp), of 25 October 2018, On the situation in the Sea of Azov, point D.
State Department’s Press Statement, ‘Russia’s Harassment of International Shipping Transiting the Kerch Strait and Sea of Azov’, Washington DC, 30 August 2018, available
European Parliament’s 2018 resolution on the situation in the Sea of Azov, op. cit., 1.
Ibid., 3. Although the European Parliament made a reference to transit passage, the EU has not otherwise claimed that the regime of transit passage is applicable to the Kerch Strait. Similarly, the United States has not submitted a protest for the applicability of the right of transit passage in the Kerch Strait.
vts services, ‘General Information’, ‘Terms and conditions of navigation services in the VTS of the Kerch Strait’, Rosmorport 2020, available
Rosmorport, op. cit., ‘Terms and conditions of navigation services in the VTS of the Kerch Strait’.
Ibid.
imo Assembly, Resolution A.857(20), Annex 1, ‘Guidelines and Criteria for VTS’, adopted on 27 November 1997, entered into force 3 December 1997.
Rosmorport, op. cit., ‘Terms and conditions of navigation services in the VTS of the Kerch Strait’.
imo Resolution A.857(20), Annex 1, op. cit., 2.3.3.
International Association of Marine Aids to Navigation and Lighthouse Authorities, iala vts Manual, (Ed. 6, iala, Saint Germain en Laye, 2016), 27.
Ibid., 43.
Traffic Management Finland, Helsinki VTS Master’s Guide, 2020, 4–5, available at:
iala vts Manual, op. cit., 27.
International Association of Marine Aids to Navigation and Lighthouse Authorities, iala Guideline 1071 – Establishment of a Vessel Traffic Service beyond Territorial Seas, (Ed. 1, 2009), 4ff.
imo Resolution A.857(20), Annex 1, op. cit., 2.3.3.
See Regulation 12 of Chapter v, International Convention for the Safety of Life at Sea (solas), adopted 1 November 1974, entered into force 25.05.1980, 1184 unts 278.