The Houthi blockade

IN July 2026, the Houthis declared a naval blockade against Saudi Arabia, targeting Saudi-linked shipping, and warning commercial vessels of any nationality against calling at Saudi ports. Vessels deemed to breach the blockade faced attack wherever they entered the Houthis’ operational reach. Attacks on Saudi tankers and energy infrastructure were followed by traffic through Bab al-Mandeb falling to its lowest level in months. By September, Houthi forces had seized strategic islands around Bab al-Mandeb and gained control of Yemen’s Red Sea coast, increasing their capacity to threaten, disrupt and potentially control maritime traffic through the strait. The conventional legal position is that naval blockade is a belligerent right associated with international armed conflict (IAC), mainly because it permits interference with neutral commercial shipping. As per this view, a non-state armed group engaged solely in a non-international armed conflict does not ordinarily have the authority to impose a blockade that is binding on neutral vessels. However, customary international law does not conclusively foreclose blockade in a sufficiently intense NIAC, particularly where an organised armed group exercises extensive territorial and governmental control and can enforce maritime restrictions. This question is particularly significant in Yemen, where there is a strong argument that the Houthis function as a de facto governmental authority rather than merely an insurgent movement. They have long controlled Sana’a, govern territory containing a substantial population, and have expanded along the Red Sea coast and around Bab al-Mandeb. Crucially, under the ICRC approach, effective governmental control, rather than global recognition alone, is central to determining de facto governmental authority. If the Houthis are treated as exercising Yemen’s governmental authority, their external hostilities may be characterised as those of Yemen itself, strengthening the argument that