Major undersea Internet cable serving South Africa offline

Some Internet users in South Africa are reporting slow speeds after repairs to the West Africa Cable System (WACS) started on Sunday.

WACS is one of the key submarine fibre cables carrying Internet traffic from Europe to South Africa. It is also a key link between South Africa and the South Atlantic Cable System (SACS), which lands in Angola.

The cable system runs from Portugal to a landing station at Yzerfontein, in the Western Cape. It has a design capacity of 14.5Tbps.

It also offers “express lanes” — including a dedicated fibre pair connecting South Africa directly to Europe, making it a critical resource for content delivery networks and South African network providers.

While many Internet providers in South Africa have sufficient backup capacity for their customers to be unaffected by the outage, some have been severely impacted.

MyBroadband has also observed more complaints from Cape Town than Gauteng. Internet service provider Cool Ideas explained this was because many networks split their networks.

Customers in the Northern region run over undersea cables that land along the East Coast, such as Seacom and EASSy, while customers in the Southern region run over West Coast cables.

“WACS emergency maintenance activity is planned to resolve a low voltage issue affecting both Power Supply Units on the Swakopmund Power Feeding Equipment,” a recent status notice said.

“The issue has been traced to a faulty Branching Unit in Namibia. As a result, the replacement of the faulty Branching Unit in Namibia is required to restore normal operation.”

According to the notice, the emergency maintenance started at 02:00 on Sunday, 1 June and is scheduled to be completed by 08:00 on 16 June 2025.

WACS will be offline for the duration of the maintenance, and the dates are subject to change depending on weather conditions.

Repair ship on site

Openserve global carrier business development and operations specialist Robert Kraai recently reported that a repair ship recovered the faulty branching unit off the coast of Namibia.

“Confirmation of good cable condition was received through the WACS representative on board the repair ship,” said Kraai, who is co-chair of the WACS operation and maintenance services committee.

“This then confirms the branching unit to be the faulty equipment.”

Kraai said the next step was to replace the faulty unit with a new one, then test the replacement to confirm it worked.

“The recovered unit will be taken to the supplier for further analysis, to determine what caused the recent abnormality with respect to its functionality.”

Kraai said the repair is happening as planned and traffic will be restored once all repair and post-repair test activities are concluded.

These must confirm signal flow from South Africa to Lisbon and then to the London point of presence.

Submarine and terrestrial network capacity consultant Roderick Beck has said that unless there are unforeseen problems, it is likely the cable will be back in service by Sunday.