International Maritime Organization

The International Maritime Organization (IMO) is the United Nations specialised agency for international shipping safety, security, and environmental standards. Founded in 1948 and headquartered in London, it sets global frameworks including SOLAS (Safety of Life at Sea) and the 1972 COLREGS. Its flag-state and port-state control systems are the primary mechanism for enforcing maritime law internationally. The IMO has 175 member states and its Secretary-General as of 2026 is Arsenio Dominguez of Panama.

The 2026 Gulf blockade exposed structural limits in IMO authority: it can issue guidance and convene emergency sessions but has no enforcement power inside waters controlled by the IRGC. Secretary-General Dominguez published a formal statement on 17 April invoking UNCLOS and explicitly rejecting tolls, fees, or discriminatory transit measures on international straits, surfacing the 1968 Traffic Separation Scheme (a tripartite framework agreed between Iran, Oman, and the IMO governing Hormuz movement for 58 years) and disclosing 20,000 seafarers and 2,000 vessels trapped in the Persian Gulf. By late June the IMO coordinated with Oman a toll-free Strait of Hormuz transit corridor and launched a state-to-state evacuation of approximately 11,000 stranded Gulf seafarers on 23 June 2026, with Iran, Oman, and the United States cooperating in the framework. On 25 June, the IRGC Navy declared the Oman-IMO corridor "unacceptable and dangerous" and ordered all vessels to coordinate on VHF Channel 16 with the IRGC instead, a direct challenge to IMO and Omani navigational authority that Left the legal status of Hormuz passage in contest. British and French planners at Northwood had earlier anchored post-war Hormuz mission planning in the IMO's 1968 Traffic Separation Scheme as the legal baseline. When Oman authorised a UK-French mine-clearance mission on its southern Hormuz route shortly before 7 July, the IMO put the number of stranded ships needing evacuation before clearance work could begin at roughly 500, the gating figure a same-day tanker attack then pushed back before clearance started.

Away from the Gulf crisis, the IMO reached a landmark on 22 May 2026 at its MSC 111 session in London, adopting the first global MASS Code (Maritime Autonomous Surface Ships). The non-mandatory code entered force on 1 July 2026 as scheduled, applies to cargo ships, keeps a human master legally responsible from ashore, and targets a mandatory framework from 1 January 2032; the Experience Building Phase framework itself will not be developed until the Maritime Safety Committee meets as MSC 112 in December 2026. Classification societies DNV and Lloyd's Register already certify autonomous vessels under their own rules; divergence during the Experience Building Phase is a flagged risk, and Nautilus International has raised unresolved liability, single-master-multiple-vessel safety evidence, and workforce questions. The Gulf blockade is the most severe single-waterway disruption in IMO history and the MASS Code is the most consequential regulatory shift in autonomous shipping; both landed within weeks of each other in 2026, and both remain live into July as the Hormuz mine-clearance and MASS oversight tracks run in parallel. On 24 July the Saudi-flagged tanker NCC Masa was struck roughly 70 nautical miles southwest of Al-Shuqaiq, sustaining minor hull damage with the crew unhurt, the first vessel hit since the Houthis declared a blockade on Saudi-linked shipping on 20 July. The incident sits within the IMO's own shipping-safety tracking, a different measure from the UN human rights office's separate count of seafarer deaths.