Map of M4 Motorway Junctions
Map of the M4 motorway junctions.
West M4
To the West the M4 joins the M5 at M4 Junction 20 which heads north to Devon Cornwall and the South West of England.
The Western end of the M4 is in South Wales Junctions 23 to 48. Bridgend is on Junctions 25 to 37, M4 Junctions 44 and 45 for Swansea, Junctions 30 to 33 for Cardiff and Junctions 24 to 28 for Newport.
East M4
At the eastern end of the M4 is London, with Junctions for Slough, Reading, Newbury, Swindon and Bristol on the way to Wales in the West.
How Do I Find M4 Traffic News?
Simply type the search words in the search facility towards the top right of this page and click "search".
Search all the latest M4 traffic news →
Latest accident or incident on the M4
The most recent accident or incident on the M4 that we are aware of.
Latest active roadworks on the M4
Roadworks live on the M4 right now.
Hardshoulder closure
20:5725 Sept 2026reported 19 min ago
- Location
- M4 eastbound between J17 and J16
- Direction
- Eastbound
- Lanes closed
- Hard shoulder closed
- Reason
- Roadworks
- Schedule
- 23:59 Tue 27 Apr 2021 → 18:00 Fri 30 July 2027
+ 2 more active roadworks - search all M4 traffic news →
Latest planned roadworks on the M4
The next planned roadworks scheduled on the M4.
M4 westbound Membury Services closure
20:5725 Sept 2026reported 19 min ago
- Location
- M4 westbound between J14 and J15
- Direction
- Westbound
- Lanes closed
- Carriageway closed
- Reason
- Maintenance work
- Schedule
- 21:00 Fri 25 Sept 2026 → 06:00 Sat 26 Sept 2026
Forecast - not confirmed
+ 3 more planned roadworks - search all M4 traffic news →
Road closed — on the overhead signs now
National Highways’ overhead signs are showing a road closure, as at 21:17 Fri 25 Sept 2026.
M48 CLOSED USE M4
Time now: Friday, 25 September 2026, 21:1720:1225 Sept 2026set 1 hr ago✓ Checked by us 21:17
M48 CLOSED
USE M4Overhead Message
WhereM49 northbound · on 1 signAlso onAlso showing on M49 signsSinceSet 20:12 Fri 25 Sept 2026We check these overhead signs at least every five minutes, but we can't guarantee a sign is still current if an incident or issue has been cleared and the sign has not been updated yet. Signs and news can each carry something the other does not - check both before you travel.
Search all the latest M4 traffic news →
Updated 21:17 Fri 25 Sept 2026
Powered by National Highways’ Transport Data Feeds.
M4 junctions — west to east
▲ WEST South Wales & Pont Abraham
- J49A48/A483Pont Abraham — M4 ends (for Llanelli, Ammanford)
- Pont Abraham servicesat J49
- J48A4138Hendy, Llanelli, Pontarddulais
- J47A48Penllergaer, Gorseinon, Swansea (west)
- Swansea West servicesat J47
- J46A48Llangyfelach, Morriston
- J45A4067Ynystawe, Clydach, Swansea Valley
- J44A48/A48Llansamlet, Swansea (east)
- J43A465Llandarcy, Neath, Heads of the Valleys
- J42A483Earlswood, Briton Ferry
- J41A48Baglan, Port Talbot (west)
- J40A48Port Talbot, Aberavon
- J39A48Cwmavon (west-facing only)
- J38A48Margam, Kenfig
- J37A4229Pyle, Porthcawl, Cornelly
- J36A4061/A4063Sarn, Maesteg, Bridgend (north)
- Sarn Park servicesat J36
- J35A473Pencoed, Bridgend (east)
- J34A4119Miskin, Llantrisant, Talbot Green
- J33A4232Cardiff West, Capel Llanilltern
- Cardiff West servicesat J33
- J32A470Coryton, Cardiff (north), Merthyr Tydfil
- J30A4232Cardiff Gate, Pentwyn
- Cardiff Gate servicesat J30
- J29A48(M)Castleton — A48(M) for Cardiff (east)
- J28A48Newport (west), Tredegar Park
- J27B4591High Cross, Newport (Rogerstone)
- J26A4051Malpas, Newport (north)
- J25aA4042Newport (Brynglas)
- J25B4596Caerleon, Newport (east)
- J24A48Coldra, Newport (east), Chepstow (A48)
- J23aA4810Magor, Llanwern
- Magor servicesat J23a
- J23M48M48 — old Severn Bridge / Chepstow
- J22M49M49 — Avonmouth link to the M5
- J21M48/A403M48 & Severn crossings, Aust
- J20M5Almondsbury — M5 interchange (Midlands / South West)
- J19M32M32 — Bristol city centre
- J18A46Tormarton, Bath, Stroud
- Leigh Delamere servicesbetween J17 and J18
- J17A350Chippenham, Cirencester
- J16A3102Swindon (west), Wootton Bassett
- J15A419Swindon (east), Cirencester, Marlborough
- Membury servicesbetween J14 and J15
- J14A338Hungerford, Wantage, Great Shefford
- J13A34Chieveley, Newbury — A34 for Oxford / Southampton
- Chieveley servicesat J13
- J12A4Theale, Reading (west)
- Reading servicesbetween J11 and J12
- J11A33Reading (central), Basingstoke (A33)
- J10A329(M)Wokingham, Bracknell, Reading (east)
- J8/9A404(M)/A308(M)Maidenhead, High Wycombe, Marlow
- J7A4Slough (west), Huntercombe
- J6A355Slough (central), Windsor, Eton
- J5A4Langley, Slough (east), Datchet
- J4bM25M25 interchange (London orbital)
- J4A408Heathrow Airport, Uxbridge
- J3A312Hayes, Southall, Heathrow (A312)
- Heston servicesbetween J2 and J3
- J2A4Brentford, Chiswick (A4)
- J1A4/A406Chiswick — A4 & North Circular (London)
▼ EAST London & the A4 / North Circular
The M4 runs ~189 miles between London and South Wales, crossing the Severn. It meets the M25 (J4b), M32 (J19), M5 (J20), M48 (J21/J23) and M49 (J22). Tap Latest M4 Traffic News and search a junction for live updates.
Also travelling on the M25?
The M4 meets the M25 London orbital motorway at Junction 4b. If your journey also uses the M25, see our sister site M25 Traffic for the latest M25 traffic news and updates in the same easy-to-use format.