Six-month long M4 work begins today and this is the list of all closures
The works started today and are expected to finish by the end of November 2025
Shaurya Shaurya 14:24, 09 Jun 2025
The work will take place over six months(Image: John Myers)
Major roadworks on the M4 that are set to take place over the next six months began on Monday, and drivers should be aware of precisely when and where the works will cause disruption.
Starting today, the work will take place between junctions and 37 and 38 close to Pyle, is said to be undertaken to 'ensure the safety and long-term resilience of the motorway'. The work consists of refurbishment being done to five bridges along the aformentioned stretch of the M4[1].
The work has been described as 'essential' to maintain safety and prevent deterioration of the road.
The work, which will span half an year, in four main phases as follows:
Preparatory works to set up the contraflow system
Starting from tonight and lasting until June 15, these include:
- June 9 (8pm) - June 10 (6am) - Overnight closure westbound for one night on the M4 between J37 Pyle to J39 Groes.
- June 10 to 12 - (8pm to 6am) - Overnight closure in both directions for two nights M4 between J37 Pyle to J39 Groes.
- June 12 (8pm) - June 13 (6am) - Overnight closure westbound for one night on the M4 between J37 Pyle to J39 Groes.
- June 13 to 15 - (8pm to 6am) - Overnight closure eastbound for two nights on the M4 between J38 Margam to J37 Pyle.
Phase one - Central reserve works
This phase will commence from June 15, 6pm, and last until July 16:
- Phase one - Central reserve works with traffic flow reduced from three lanes to two lanes in each direction
- A 50mph speed limit will be in place during this time for safety.
- Further details on later phases of works will be published closer to the time.
The motorway will remain open along two running lanes in both directions while the works take place.
The closures put in place will only be overnight, and are going to be well-signposted in advance.
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To ensure the safety of drivers and workers, temeporary speed limits will also be put in place.
As junctions 37 and 38 will operational during phases one to four, no diversion route will necessary.
However, when the road is fully closed to install traffic management, drivers will be diverted via the A4229 and A48.
Motorists travelling west will be directed off the M4 at Junction 37, rejoining at Junction 39.
Cabinet Secretary for Transport and North Wales Ken Skates said: "Fixing and maintaining our roads and making them more resilient is a priority for us.
Article continues below"I understand the works will cause disruption and I'd like to thank motorists for their patience whilst the work is taking place, however it is important it is carried out during periods of drier and warmer weather[3] to ensure it can be done effectively."