The growing relationship between Yemen’s Houthi movement and Somalia’s al-Shabaab matters not simply because two armed groups are cooperating, but because their expanding links are connecting two conflict environments on opposite sides of the Gulf of Aden. The relationship now involves weapons transfers, military training, personnel movements, drone technology and logistical links. US officials have recently warned that these ties pose an escalating threat to regional stability and international trade. As fighting around the Bab el-Mandeb has intensified, the possibility that capabilities developed on one side of the waterway could reinforce insecurity on the other has gained greater strategic significance.

However, the relationship is not new. UN investigations have documented al-Shabaab fighters travelling to Yemen for military training, including rifle use, anti-aircraft weapons and improvised explosive devices. The UN Panel has also documented weapons moving from Yemen to Somalia and described a relationship that had evolved beyond simple arms trafficking. In 2025, investigators received evidence that two Houthi military engineers travelled to Jilib to train al-Shabaab members in improvised explosive device manufacturing, drone adaptation and weapons maintenance. The same investigation found that nearly 400 Somali nationals had been facilitated to travel to Houthi-controlled areas for military and ideological training.

More recent evidence suggests that these contacts form part of a broader Houthi effort to expand relationships and logistical networks along the African side of the Red Sea and Gulf of Aden.  Several 2026 assessments also describe the Houthis as cultivating ties with several African actors, including Eritrea and al-Shabaab, despite differences in ideology, religion and political objectives. The significance is not that these relationships already constitute a coherent alliance, but that initially transactional exchanges can, over time, generate greater capabilities, trust and mutual dependence.

This does not mean that the Houthis and al-Shabaab have become a formal military alliance. The UN has previously characterised their relationship as transactional or opportunistic rather than ideological. Their political objectives, religious traditions and operational environments remain different. But formal alliance structures are not necessary for cooperation to produce strategic consequences. More significant, however, is the accumulation of complementary capabilities: the Houthis provide weapons, technical expertise, and drone technology, while al-Shabaab contributes established personnel networks and operational access along sections of the Somali coast. This synergy amplifies the  strength of both groups, enabling each to achieve outcomes that would be unattainable alone.

The Gulf of Aden is where those capabilities acquire heightened importance. The Houthi and al-Shabaab threats have generally been treated as separate security problems, but that distinction is becoming increasingly difficult to sustain. The Houthis have demonstrated their ability to use missiles and drones against maritime targets, while renewed fighting has concentrated international attention on the Bab el-Mandeb. Saudi-backed Yemeni forces have launched an offensive around the strait, while the Houthis have responded with missile and drone attacks.

Recent reporting suggests that the relationship between the Houthis and al-Shabaab is shifting from limited contact to more direct operational collaboration, including arms transfers, training, and technical support. Although regional security sources have voiced concerns about Houthi attempts to expand surveillance operations from the Somali coastline, notably by providing communications and radar equipment. These activities do not give al-Shabaab the capacity to dominate the Gulf of Aden or close the Bab el-Mandeb, they nonetheless reflect a growing convergence in capabilities that could complicate security calculations for maritime actors in the region.

The core strategic risk is the emergence of  a coordinated maritime threat from both the Arabian and African sides of the Gulf of Aden. If al-Shabaab acquires advanced expertise with drones, explosives, and coastal surveillance, its insurgent infrastructure could become a critical asset for those seeking to monitor or disrupt maritime traffic. At the same time, the Houthis could expand their operational reach, intelligence gathering, and logistical networks on the African coast. Importantly, neither group requires conventional naval power for their cooperation to matter; instead, cost-effective asymmetric tactics could impose disproportionate costs on shipping, ports, and maritime infrastructure.

The relationship also intersects with illicit maritime networks that already connect Yemen and Somalia. UN reporting has previously identified discussions in which al-Shabaab sought advanced weapons and training in exchange for increasing piracy activity in the Gulf of Aden and off the Somali coast. The UN has also documented weapons and explosives moving between Yemen and Somalia through coastal routes and small vessels. This does not establish that Houthi-al-Shabaab cooperation has produced a sustained piracy campaign. It demonstrates, however, that maritime and logistical channels already exist through which weapons, personnel and technical expertise can move between the two sides of the Gulf.

This makes the development more than another dimension of Somalia’s counterinsurgency. An al-Shabaab operating with limited external support presents one type of security challenge; an al-Shabaab with sustained access to external training, weapons and technical expertise presents another. Disrupting the external networks that support the group therefore becomes increasingly important to counterterrorism efforts inside Somalia. The objective is not to portray every maritime movement between Yemen and Somalia as part of an integrated militant network, but to identify and disrupt the specific channels that allow such cooperation to develop.

The implications extend beyond Somalia and Yemen. Djibouti’s position near the Bab el-Mandeb and its concentration of commercial and military infrastructure make any deterioration in the surrounding maritime security environment consequential for the country. Ethiopia is also directly affected because much of its international trade depends on maritime access through Djibouti. A sustained deterioration in security on either side of the Gulf could therefore generate consequences far beyond the territory controlled by the two armed groups.

Regional governments must prioritise stopping emerging links from solidifying into an established operational network. Intelligence cooperation should focus on the movement of fighters, weapons, explosives specialists, and drone technology between the Houthis and al-Shabaab. Coastal surveillance should be strengthened, and maritime authorities need improved mechanisms to detect suspicious small-vessel movements. Financial and logistical networks connecting armed groups across the Gulf should receive the same attention as arms transfers themselves.

International maritime initiatives can contribute to this effort, but regional ownership will remain essential. Somalia, Djibouti, Ethiopia and other states surrounding the Red Sea and Gulf of Aden have a direct interest in preventing the maritime space from becoming an extension of land-based conflicts. The objective should not be to militarise every aspect of the Gulf of Aden, but to ensure robust intelligence-sharing, coastal surveillance, and maritime awareness that can detect emerging networks before they become operationally mature.

The deeper lesson is that the geography of the Red Sea security crisis is changing. The Houthi and al-Shabaab theatres can no longer be treated as entirely separate when weapons, personnel, technology and maritime interests increasingly connect them. The Gulf of Aden is becoming more than the space between two conflicts; it is becoming a channel through which capabilities developed in one theatre can influence the other.

Whether the Houthi-al-Shabaab relationship develops into a durable operational partnership remains uncertain. But waiting for a formal alliance would be a strategic mistake. The greater risk arises from incremental convergence through the transfer of capabilities and personnel, as well as expanded logistical access. Preventing that process from becoming durable should therefore be a priority for Somalia, Djibouti and the wider international maritime community. The central challenge is not simply protecting the Bab el-Mandeb from threats originating in Yemen. It is ensuring that insecurity does not become established on both sides of the Gulf of Aden.

By Abraham Abebe, Researcher, Horn Review