KeNHA will close the Ole Sereni–Kikuyu section for the October 25 marathon and direct motorists to alternative routes.
The Southern Bypass closure will disrupt Nairobi traffic as KeNHA clears the route for the 2026 Standard Chartered Nairobi Marathon. The affected section runs between Ole Sereni Interchange and Kikuyu town.
In its October 18 public notice, the Kenya National Highways Authority set out the closure period. It will run from midnight on Saturday, October 24, until 2pm on Sunday, October 25.
The restriction aims to give marathon participants a secure route during the annual event. The race, which attracts thousands of runners and spectators, takes place on Sunday, October 25.
Southern Bypass closure and main diversion
KeNHA Director-General Luka Kimeli urged motorists to plan their journeys and use the designated alternatives. The authority identified Mombasa Road and Uhuru Highway as the main diversion.
Drivers should use Mombasa Road, also known as the A8, from Ole Sereni Interchange through Uhuru Highway. The same alternative applies to motorists travelling in the opposite direction.
KeNHA also asked road users to obey traffic signs throughout the affected areas. Drivers should follow directions from police officers and traffic marshals managing traffic along those roads.
Routes for Kikuyu, Karen and Dagoretti
Motorists heading to Kikuyu, Dagoretti and Karen will need to choose alternatives based on their destinations. However, drivers travelling between Kikuyu and Dagoretti can use sections of the bypass where access remains available.
For journeys between Karen and Kikuyu, the traffic plan directs motorists through Dagoretti Road. Diversions towards Langata Road and Galleria Mall also include Dagoretti Road.
Meanwhile, drivers travelling between Mombasa Road and the Inland Container Depot must follow the designated diversions. Vehicles approaching Emara Ole Sereni from Mombasa Road will use the route through Nextgen Mall.
KeNHA also advised motorists heading towards Kikuyu to consider Waiyaki Way. Depending on their starting point, they can alternatively use routes through Ngong Road and Mbagathi Way.
Lorries and trailers to use Waiyaki Way
The restrictions also cover trailers and lorries using the affected section during the marathon. KeNHA will direct these heavy commercial vehicles onto Waiyaki Way while the closure remains in force.
The authority urged motorists to allow extra travel time, particularly for journeys to the airport. That advice also applies to trips to industrial areas and residential estates served by the bypass.
The road links Mombasa Road with Langata, Dagoretti and Kikuyu, supporting travel across southern and western Nairobi. For clarification on the traffic arrangements, KeNHA advised the public to contact its official lines.
