The Cardiff Half Marathon is almost here, and with thousands of runners taking to the streets comes a Sunday of major road closures across the city.
The race takes place on Sunday 4 October 2026, with thousands of runners expected to tackle the 13.1-mile route through Cardiff and Penarth.
If you’re not running, it’s worth knowing what’s happening before heading into the city. Roads will close across Cardiff city centre, Cathays, Roath, Cardiff Bay and other parts of the route, with some restrictions beginning several days before the race.
The first closures actually begin on Wednesday 30 September, as preparations get underway around the Civic Centre.
From 5am on Wednesday 30 September until 11.59pm on Monday 5 October, College Road will close between Museum Avenue and King Edward VII Avenue.
Further closures begin on Thursday 1 October, with King Edward VII Avenue closed between Boulevard de Nantes and City Hall Road until Monday 5 October.
From 5am on Friday 2 October, additional restrictions will be introduced around King Edward VII Avenue, Museum Avenue, Gorsedd Gardens Road and City Hall Road as organisers prepare the race village and finish area.
Vehicle access to private parking and for deliveries will be maintained in affected Civic Centre areas until 9am on race day.
The biggest disruption will, unsurprisingly, come on Sunday 4 October.
From 4am until midday, closures will affect North Road south of Boulevard de Nantes, the A4161 towards Kingsway, Kingsway, Duke Street, Castle Street and Cowbridge Road East towards Cathedral Road.
North Road between Colum Road and Boulevard de Nantes will also close between 6am and 10.45am.
Later in the day, Colum Road and part of Park Place will close between 10am and 3.10pm.
The main race itself will require a huge rolling road closure between 8.30am and 3.10pm, with roads reopening behind the runners as soon as organisers consider it safe to do so.
The route heads from Cowbridge Road East through Wellington Street, Leckwith Road and Sloper Road before reaching Penarth Road and heading towards Cardiff Bay Barrage.
Runners will cross into the Vale of Glamorgan around Terra Nova Way and Penarth Portway before returning through Cardiff Bay via Harbour Drive, Roald Dahl Plas, Britannia Quay, Pierhead Street and Bute Place.
From there, the race continues along Lloyd George Avenue before heading through Herbert Street, Tyndall Street, East Tyndall Street and Windsor Road.
The course then makes its way through the eastern side of the city, passing Adam Street, Fitzalan Place, West Grove, Richmond Road and Albany Road before continuing through Penylan and Roath.
Roads affected in this section include Penylan Road, Blenheim Road, Marlborough Road, Ninian Road, Fairoak Road, Lake Road East and Lake Road West.
The final section takes runners along Fairoak Road, Cathays Terrace and Corbett Road before reaching the finish on Museum Avenue.
There will also be temporary security measures around several residential areas. Access to Beatty Avenue will only be possible from Lake Road North, while arrangements will be in place for Jellicoe Gardens, Keys Avenue and Tyrwhitt Crescent. Access to Queen Anne Square will be managed through Colum Road and Corbett Road, while Lady Mary Road will close between Maryport Road and Lake Road East.
In Cardiff Bay, a managed diversion will help residents and businesses get in and out of the area during the race, using Celerity Drive, Craiglee Drive, Letton Way, Lloyd George Avenue and Bute Place.
Access to Cathays Cemetery will also be maintained via Allensbank Road until Fairoak Road reopens.
With such a large part of Cardiff affected, anyone travelling across the city on Sunday 4 October is being advised to plan ahead, allow extra time and expect delays.
The good news is that many of the race-day restrictions are rolling closures, meaning roads will begin reopening once the final runners have passed and it is safe to do so.
The Cardiff Half Marathon takes place on Sunday 4 October 2026, with rolling road closures along the course between approximately 8.30am and 3.10pm.
