Map of the M3 Motorway Junctions
All 15 junctions on the M3 — J1 to J14, plus J4A between J4 and J5 — from Junction 1 at Sunbury in the north-east to Junction 14 at the M27 outside Southampton. Each one is listed with the road it connects to and the places it serves — so you can pin down exactly where an M3 closure, incident or set of roadworks actually is before you set off.
NORTH-EAST — London, Sunbury & the A316
- J1A308Sunbury Cross — Staines, Shepperton & Hampton
- J2M25M25 Junction 12 — for Heathrow, the M4 and the M40
- J3A322Lightwater, Bagshot & Bracknell
- J4A331Frimley, Camberley & Aldershot
- J4AA327Fleet & Farnborough
- J5A287Hook, Odiham & Farnham
- J6A30 / A339Basingstoke & Alton
- J7A30Basingstoke (south) & Old Basing
- J8A303Andover, Salisbury & the West Country
- J9A34 / A272Winchester (north), Newbury & Oxford
- J10A31 / B3330Chilcomb Interchange — Winchester (east)
- J11A3090Winchester (south), Compton & Twyford
- J12A335Eastleigh & Chandler’s Ford
- J13A335Chilworth, Southampton Airport & Southampton (north)
- J14M27M27 — Southampton, Portsmouth & Bournemouth
SOUTH-WEST — the M27, Southampton & the South Coast
Search all the latest M3 traffic news →
Latest accident or incident on the M3
The most recent accident or incident on the M3 that we are aware of.
M3 Eastbound Jct 2 to Jct 1 carriageway closure
00:462 Sept 2026reported 10 min ago
- Location
- M3 eastbound between J2 and J1
- Direction
- Eastbound
- Lanes closed
- Carriageway closed
- Reason
- Other
- Schedule
- 22:00 Tue 1 Sept → 05:30 Wed 2 Sept
Latest active roadworks on the M3
Roadworks live on the M3 right now.
A303 eastbound crematorium to M3 carriageway closure
00:462 Sept 2026reported 10 min ago
- Location
- M3 eastbound between J8 and J7
- Direction
- Eastbound
- Lanes closed
- Carriageway closed
- Reason
- Roadworks
- Schedule
- 20:54 Tue 1 Sept → 06:00 Wed 2 Sept
+ 1 more active roadworks - search all M3 traffic news →
Latest planned roadworks on the M3
The next planned roadworks scheduled on the M3.
Search all the latest M3 traffic news →
Updated 00:57 Wed 2 Sept
Powered by National Highways’ Transport Data Feeds.
How much traffic is there between each M3 junction?
These are the Department for Transport’s 2025 figures for every measured stretch of the M3 mainline, in order from Junction 1 down to Junction 14. The final column says whether the figure comes from a physical count or is the Department’s own estimate — we publish both, and we say which is which.
| Stretch | Miles | Vehicles per day | Basis |
|---|---|---|---|
| J2 to J1 Sunbury | 5.8 | 62,848 | Estimated |
| J3 Lightwater to J2 (M25) | 7.6 | — | two counts |
| — J3 to Kitsmead Lane flyover | 5.5 | 123,417 | Counted |
| — Kitsmead Lane flyover to M25 J12 | 2.1 | 113,905 | Counted |
| J4 Frimley to J3 Lightwater | 4.5 | 118,589 | Counted |
| J4A Fleet to J4 Frimley | 2.1 | 93,372 | Counted |
| J5 Hook to J4A Fleet | 7.5 | 96,243 | Counted |
| J6 Basingstoke to J5 Hook | 4.8 | 103,624 | Counted |
| J7 to J6 Basingstoke | 4.9 | 94,624 | Estimated |
| J8 A303 to J7 | 1.2 | 101,834 | Estimated |
| J9 Winchester to J8 A303 | 11.0 | 56,135 | Counted |
| J9 to J10 Chilcomb | 1.4 | 110,741 | Counted |
| J10 Chilcomb to J11 Compton | 0.8 | 126,217 | Counted |
| J11 Compton to J12 Eastleigh | 3.5 | 128,023 | Counted |
| J12 Eastleigh to J13 Chilworth | 1.7 | 130,785 | Counted |
| J13 Chilworth to J14 (M27) | 1.2 | 140,750 | Counted |
The busiest measured stretch of the M3 is the last mile and a bit into the M27, at 140,750 vehicles a day. The quietest is the long run between Junction 9 and Junction 8, at 56,135 — the M3 carries two and a half times more traffic at its Southampton end than it does across the middle of Hampshire.
Where a stretch is split between two count points we show both rather than picking one, because they are genuinely different measurements of different pieces of road.