M3 junction 9 closes 9pm Friday 21 August to 6am Monday 24 August, closing the A34, A33 and A272 too. The diversions, and the ways round Winchester.
Everything that leaves Winchester by road funnels through one of about four places, and National Highways is currently rebuilding the busiest of them. The M3 junction 9 improvement scheme has already taken the northbound entry slip road out of service until winter 2027, and it closes the whole junction for three weekends this summer. The next of those weekends starts at 9pm on Friday 21 August 2026.
This page covers what is shut and when, then the parts that stay useful between updates: the routes that actually matter around the city, where to park, and the park and ride prices that make driving into the centre unnecessary.
The M3 junction 9 weekend closure, 21 to 24 August
The junction 9 roundabout closes from 9pm on Friday 21 August to 6am on Monday 24 August 2026. Traffic on the M3 itself keeps running through the junction, but the slip roads and the local roads feeding the gyratory all shut (National Highways, M3 junction 9 improvements).
Closed for that weekend:
- M3 junction 9 slip roads, entry and exit, in both directions.
- A34 southbound from Bullington Cross.
- A34 northbound as far as Three Maids Hill, which also closes the A33 northbound.
- A33 southbound from the Cart and Horses junction.
- Easton Lane in both directions at the Easton Lane roundabout.
- A272 in both directions from the Spitfire roundabout on the A31.
A third weekend closure follows from 9pm on Friday 11 September to 6am on Monday 14 September 2026. The first, from 31 July to 3 August, has already happened. Signed diversions are in place on each, and National Highways publishes the maps on the scheme page.
The closure that lasts until winter 2027
The weekend closures end. The one that will shape journeys for more than a year does not. Since 9pm on Friday 31 July 2026 the M3 junction 9 northbound entry slip road has been closed, and it stays closed until winter 2027. There is no access to the M3 northbound from the junction 9 roundabout for that whole period.
If you normally join the M3 towards Basingstoke and London at junction 9, you now need a different plan for every trip: either the A34 and the A303, or south to junction 10 or 11 and back up. Factor it into school runs and airport departures rather than discovering it at the roundabout.
What is being built, and why it takes so long
The scheme turns junction 9 from a roundabout into a free-flowing interchange, so that traffic moving between the M3 and the A34 no longer has to stop. National Highways puts the cost at £268 million to £322 million, with a Development Consent Order granted on 16 May 2024, construction starting in 2024 to 2025 and completion inside the 2025 to 2030 road period.
The work includes free-flow links between the M3 and A34 in both directions, widening the M3 from three lanes to four through the junction, two new bridges on the gyratory and a longer southbound slip road. When the scheme was consulted on, the government put the traffic through the junction at 110,000 vehicles a day, more than 6,000 an hour at peak, including over 5,500 lorries (GOV.UK press release). That volume is why the junction backs up onto the motorway, and why the rebuild is being done in stages rather than in one go.
The routes that matter around Winchester
Winchester’s road network is simple enough to hold in your head, which helps when one part of it fails.
- M3 junctions 9, 10 and 11. Junction 9 is the northern gateway and the A34 interchange. Junction 10 serves the east of the city off the A31 and Alresford Road. Junction 11 is the southern one, for St Cross, the hospital and Bar End. When junction 9 is shut, 10 and 11 carry the load.
- A34 north. The route to Newbury, Oxford and the Midlands, and the reason junction 9 handles so many lorries. Closures here push traffic through Three Maids Hill and Kings Worthy.
- A33 and Andover Road. The old road north through Kings Worthy and Headbourne Worthy, and the first thing to clog when the A34 shuts.
- A31 and the A272. East towards Alresford and Alton, and the Spitfire roundabout that ties the A31 to the A272 and the M3.
- A3090 Romsey Road. West past the hospital and the university towards Hursley and Romsey.
- Easton Lane and Winnall. The link between junction 9 and the city’s main industrial estate, and part of most closure diversions.
Beyond the city, the district’s traffic runs on B roads and lanes: the B3035 to Bishop’s Waltham, the B2177 through Wickham, and the network around Denmead that feeds towards the A3 and Waterlooville.
Park and ride, and where to leave the car
Winchester’s park and ride is the practical answer to city centre congestion, and it is cheap. Five car parks, 2,137 spaces in total: South Winchester and Pitt on the western side, and Barfield, Barfield Phase II and St Catherine’s to the east (Winchester City Council).
The prices published by the council are:
| Ticket | Price | Notes |
|---|---|---|
| Standard day | £3.50 | Car park plus return bus for the driver and up to six passengers |
| Off-peak, after 10:30am Mon to Fri | £3.00 | Same coverage, later start |
| East Winchester, Saturday 3 hours | £1.80 | Barfield and St Catherine's |
| East Winchester, after 4pm Mon to Sat | Free | Barfield and St Catherine's |
| Annual season ticket | £644 | For regular commuters |
Buses run every seven minutes at peak on weekdays, every 12 minutes off-peak and all day Saturday, and every 15 to 20 minutes after 6pm. Service hours are 6:25am to 7:30pm Monday to Friday and 7am to 6:30pm on Saturday. There is no service on Sundays or public holidays, which catches people out at Christmas and on bank holiday weekends, and the machines take coins only.
For the train, Winchester station has 464 parking spaces including 10 accessible bays (National Rail). Our guide to Winchester trains to London covers the times and season ticket prices.
Where to check before you set off
- National Highways road closure report for the motorway and trunk road network, including the M3 and A34.
- The M3 junction 9 scheme page for diversion maps and the next set of dates. The project team can be reached on 0300 123 5000 or at M3Junction9Improvements@nationalhighways.co.uk.
- Hampshire County Council is the highway authority for everything that is not a motorway or trunk road, so gas, water and resurfacing works on city streets are listed through its roadworks service.
Dates move at short notice, particularly when weather stops overnight work. Check the scheme page on the Friday before a planned weekend closure rather than relying on a date read weeks earlier.
Have your say
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