The world is getting a live demonstration of what happens when a fifth of its oil is forced through a single, contested waterway. Since late February, Iran’s blockade of the Strait of Hormuz has slashed tanker traffic and rattled global energy markets, with Brent crude trading at around US$82/barrel this week.

The internet, it turns out, shares this design flaw. A new report by the International Advisory Body on Submarine Cable Resilience (IAB) – convened by the International Telecommunication Union and the International Cable Protection Committee – warns that subsea cable chokepoints have become a “systemic risk”.

Global internet traffic is “often subject to geographical concentration in a limited number of chokepoint corridors”, the report found, naming the Luzon Strait, the Strait of Malacca and the Red Sea corridor among them. “These dense clusters amplify systemic risk; a single natural hazard or geopolitical disruption in these corridors can cause multiple systems to fail simultaneously.”

The numbers are worrying. The Bab el-Mandeb Strait at the southern entrance to the Red Sea is the most concentrated stretch of water in the world, with at least 17 cables – carrying an estimated 17-20% of global internet traffic – squeezing through a channel less than 23km wide. The Suez corridor funnels an estimated 90% of Europe-Asia communications through shallow waters for more than 160km.

Cables also thread the Strait of Hormuz itself to serve Iran, Iraq, Kuwait, Bahrain and Qatar – a dependency Iranian state-aligned media has already suggested exploiting by charging tech giants “rent” for cables crossing its waters.

Chokepoint effect

Africa has felt the chokepoint effect directly. When the crippled cargo ship Rubymar – abandoned after a Houthi missile strike – dragged its anchor through the Red Sea in February 2024, it severed three cables, including Seacom’s, which carries a large share of traffic between South Africa, East Africa and Europe. Repairs were delayed for months awaiting permits in Yemeni-controlled waters, severely denting Seacom’s bottom line.

Why do operators keep laying cables in the same crowded corridors? Economics, the report says: building along an established route, where landing stations and regulatory approvals already exist, is 15-30% cheaper than pioneering a new one. This “lock-in” effect continues to funnel new systems into the very corridors operators already know are vulnerable.

Read: Seacom 2.0: huge new subsea fibre system planned for Africa

There is also a conspicuous gap. The report attributes more than 80% of the 150-200 annual cable faults to accidents – fishing gear and dragged anchors – and concedes, in a moment of unusual candour, that “while the IAB recommendations focus heavily on accidental damage (fishing and anchoring), they largely avoid explicit discussion of wilful misconduct” – tampering or sabotage. It also acknowledges why: “states may be reluctant to share even anonymised data if it highlights vulnerabilities in regions critical to their national security”, and the global cable network is splitting into “distinct US and Chinese ecosystems, which complicates international cooperation on repair and data sharing”.

Yet suspected deliberate tampering is no longer hypothetical. In the Baltic Sea, a string of incidents has seen ships linked to Russia and China drag anchors across cables and pipelines: the Balticconnector gas pipeline and telecoms cables in October 2023; the C-Lion1 and Lithuania-Sweden cables in November 2024; and the Estlink 2 power cable plus four telecoms cables on Christmas Day 2024, allegedly by the tanker Eagle S. That last repair took more than seven months and cost up to €60-million (about R1.1-billion) – and in October 2025 the Helsinki district court dismissed the case against the ship’s crew on jurisdictional grounds, ruling that under the UN Convention on the Law of the Sea the cable cut was an “incident of navigation” that only the ship’s flag state or the crew’s home countries could prosecute. The ruling laid bare how poorly international law protects cables in open water.

Taiwan went further: in July 2025 it jailed the Chinese captain of the Hong Tai 58 for three years for deliberately dragging an anchor across the Taiwan-Penghu No 3 cable – the island’s first such conviction amid what it calls Chinese “grey zone” pressure. Beijing denies involvement, calling cable damage a “common” maritime occurrence.

Layered on top of the geographic concentration is a newer threat. “Changing weather patterns and environmental pressures are emerging as important risk factors, affecting coastal landing infrastructure, seabed stability and long-term network planning,” the report found.

Storm surges are scouring cables and undermining shore infrastructure, and heavier river flooding is triggering submarine landslides that can snap multiple cables at once. East and West Africa appear repeatedly on the report’s hotspot lists, and the Congo River system – where turbidity currents caused South Africa’s dual cable breaks in 2020 and 2023 – is flagged as an area where climate change could make such landslides more likely.

Single repair ship

The stakes of inaction are quantified in the report itself. When the January 2022 Hunga Tonga-Hunga Ha’apai eruption severed Tonga’s only cable, the country endured “near-total digital isolation for 61 days”, with damages and losses of about $182-million (R3-billion) – equivalent to 38.7% of its GDP. As TechCentral reported this week, Africa’s own buffer against such a scenario is thin: a single repair ship, based in Cape Town, guards most of sub-Saharan Africa’s connectivity.