Turkish Straits transit guide: Bosphorus and Dardanelles rules in 2026

The Turkish Straits — the Istanbul Strait (Bosphorus), the Sea of Marmara and the Çanakkale Strait (Dardanelles) — are the only sea link between the Black Sea and the Mediterranean. They are also among the most demanding waterways in the world: narrow and winding, with strong currents and dense local traffic running through the middle of a city of more than 15 million people. This guide summarises the rules in force in 2026 and the practical steps behind a smooth transit.

The waterway at a glance

• Length: the vessel traffic service area covers 164 nautical miles — 17 nm in the Istanbul Strait, 110 nm across the Sea of Marmara and 37 nm in the Çanakkale Strait.
• Width: the Istanbul Strait narrows to about 700 metres, with several sharp alterations of course; the Çanakkale Strait narrows to about 1.2 km.
• Traffic in 2025: 40,172 transits of the Istanbul Strait and 44,468 of the Çanakkale Strait — 84,640 in total — carrying 422.8 and 570.3 million tonnes of cargo respectively, according to official Ministry statistics.

The legal framework

The Montreux Convention (1936)

Passage is governed by the Montreux Convention Regarding the Regime of the Straits. In time of peace, merchant vessels enjoy complete freedom of transit and navigation through the Straits, by day and by night, under any flag and with any kind of cargo. Pilotage and towage remain optional. For ships passing in transit without calling at a port in the Straits, Türkiye may levy only the charges listed in the Convention — for sanitary control, for lighthouses and light and channel buoys, and for life-saving services — calculated on the ship's net tonnage.

Transit dues in 2026

The dues are calculated from the US dollar value of the gold franc used in the Convention. That value stayed at USD 0.8063 from 1983 until 7 October 2022, when it was raised to USD 4.08. It has been revised every 1 July since then — to USD 4.42 in 2023, USD 5.07 in 2024 and USD 5.83 in 2025 — and has stood at USD 6.70 since 1 July 2026. Ask your agent for a pre-calculation based on your ship's tonnage certificate.

Traffic regulations

Navigation is regulated by the Turkish Straits Maritime Traffic Regulation (Türk Boğazları Deniz Trafik Düzeni Yönetmeliği), published in the Official Gazette on 15 August 2019 and amended in December 2020; it replaced the regulations of 1998. An implementation directive of the Ministry of Transport and Infrastructure, in force since 1 January 2024 and revised in 2025, sets the operational details. Among the key rules:

• A speed limit of 10 knots over the ground, which a ship may exceed only after informing the VTS if it needs more speed to keep steerage way.
• A "large ship" is one of 200 metres length overall or more; a "deep-draught ship" has a maximum draught of 15 metres or more.
• Ships in non-stop transit may anchor at designated anchorages for up to 168 hours with VTS permission, without obtaining free pratique.

Reporting to the VTS

Traffic is managed by the Turkish Straits Vessel Traffic Service, operated by the Directorate General of Coastal Safety (KEGM) from centres at İstinye (Istanbul) and Akbaş (Çanakkale).

• Sailing Plan 1 (SP-1): ships of 500 GT and above and ships carrying dangerous cargo file it at least 24 hours before arriving at the strait, or at least 6 hours before leaving a Marmara port. Longer notice applies to bigger ships: 48 hours for ships of 200–300 metres or with a draught over 15 metres, and 72 hours for ships of 300 metres and above.
• Sailing Plan 2 (SP-2): reported to the VTS centre by VHF 2 hours or 20 nautical miles before the strait entrance, whichever comes first.
• Position report: ships of 20 metres and above report 5 nautical miles before the entrance.
• Delays: if the ship will reach the strait more than 2 hours later than declared, the VTS must be told. A wrong or missing report costs the ship its place in the transit queue.
• P&I cover: ships carrying dangerous cargo, ships of 300 GT and above and towing vessels must hold P&I insurance covering wreck removal, pollution and third-party liabilities; the agent declares it in the SP-1.

Pilotage

For ships in non-stop transit, pilotage is strongly recommended but not compulsory, in line with the Montreux Convention. Pilotage and towage in the Straits are provided only by KEGM. In practice a majority of ships take a pilot: in 2025, 61% of Istanbul Strait transits and 54% of Çanakkale Strait transits were piloted. Ships calling at a port inside the Straits change from a strait pilot to a port pilot at designated points.

Large ships and dangerous cargoes

The implementation directive sets additional conditions for the most demanding transits. The main ones are below; because the directive was revised in 2025, confirm the current thresholds with your agent before planning.

• Ships of 300 metres and above (except passenger ships), push or alongside tows and floating structures transit in daylight with a pilot. The agent applies to the regional harbour master at least 10 days in advance, and a commission sets the transit conditions.
• Daylight transits in the Istanbul Strait apply to all ships of 250 metres and above, ships of 200 metres and above carrying dangerous cargo (other than container and ro-ro ships), deep-draught ships and towed transits; a pilot and escort tugs are strongly recommended for them.
• Gas carriers: LNG carriers transit in daylight with a pilot and tug escort while the strait is closed to opposing traffic; LPG carriers of 150 metres and above transit in daylight with a pilot and tug.
• Current and visibility: with a current of 6–7 knots traffic runs in one direction only, and above 7 knots it is suspended. When visibility falls to 1 mile or less, traffic becomes one-way and large, deep-draught and dangerous-cargo ships are not admitted; at half a mile or less the strait is closed in both directions.

Planning a smooth transit

• Appoint your agent early. The agent files the reports, arranges pilots and tugs, settles the dues and keeps you informed of the traffic and weather picture.
• Allow for waiting time. Strong currents, poor visibility and one-way traffic windows for large ships can mean hours or days at anchor.
• Keep documents and equipment in order. Certificates, P&I evidence and the condition of steering, propulsion and anchoring gear all matter — a defect reported on approach can hold up a transit.
• Combine the passage with port services. Many owners use the Istanbul or Çanakkale anchorages for bunkers, provisions, spares and crew changes; plan these with your agent before arrival.

Our Istanbul team handles transits, port calls and husbandry services in the Turkish Straits around the clock. See our ship agency service.