A major programme of maintenance on the M3 Lagan Bridge in Belfast will begin on Friday 14 August 2026.

This is the third phase of bridge bearing replacements, following earlier phases in 2024 and 2025. So far, 18 bearings have been replaced; a further six are now scheduled, affecting the bridge's on and off slip roads.

Work is planned across three summer weekends: Friday 14 to Monday 17 August; Friday 21 to Monday 24 August; and Friday 28 to Monday 31 August 2026. During these periods, access to the M3 on and off slips will be restricted.

From 9pm on Friday 14 August until 6am on Monday 17 August, the westbound carriageway will be affected and the M3 Middlepath Street on-slip (westbound) will be closed. Traffic from the city centre wishing to access the M3 will be diverted via A2 Middlepath Street, A2 Bridge End, A2 Ann Street, A2 Victoria Street, A2 Dunbar Link, A2 Great Patrick Street and A2 York Street.

In addition, lanes 1 and 2 will be closed westbound with no access or egress permitted to the M3 Nelson Street off-slip (westbound) towards the A12 Westlink. Drivers joining the M3 directly from the Sydenham Bypass heading for the Westlink or north/west Belfast will be unable to exit until the M2 Junction 1 Fortwilliam Roundabout off-slip road, where they will be redirected onto the M2 southbound towards Nelson Street.

From 9pm on Friday 21 August until 6am on Monday 24 August, the eastbound carriageway will be affected and the M3 Nelson Street on-slip (eastbound) will be closed. The signed diversion will route traffic via A2 Nelson Street, A2 Dunbar Link, A2 Victoria Street, A2 Waring Street, A2 Albert Square, A2 Donegall Quay, A2 Queen Elizabeth Bridge and A2 Middlepath Street. From Friday 28 August until 6am on Monday 31 August, the westbound carriageway will again be affected, with the M3 Middlepath Street on-slip (westbound) closed. City-centre traffic seeking to join the M3 will once more be diverted via A2 Middlepath Street, A2 Bridge End, A2 Ann Street, A2 Victoria Street, A2 Dunbar Link, A2 Great Patrick Street and A2 York Street.

Lanes 1 and 2 will also be closed westbound over this period, with no access or egress to the M3 Nelson Street off-slip (westbound) towards the A12 Westlink. As before, drivers will be unable to leave the motorway until the M2 Junction 1 Fortwilliam Roundabout off-slip road, after which they will be redirected onto the M2 southbound towards Nelson Street.

Minister Kimmins said: "The M3 bridge is a key structure which carries over 90,000 vehicles and these specialist works are essential to ensure that the structure remains in a sound condition for future use."

"While closures are not as extensive as previous years, some traffic disruption can still be expected and I would advise road users to allow extra time for their journey, particularly if travelling to the ports or airports."

"I would like to thank the travelling public for their patience and cooperation while these important bridge maintenance works are completed."

The works have been scheduled for summer weekends when traffic flows are typically lower. Diversion routes will be clearly signposted, and road users are asked to comply with temporary traffic management for the safety of the public and the workforce. All activity is subject to favourable weather.

A traffic schematic, including diversion details, is available at: www.infrastructure-ni.gov.uk/publications/m3-road-closure-august-2026. For live traffic information on this and other schemes, visit: www.trafficwatchni.com.

The scheme will be delivered by Highway Management (City) Ltd under its DBFO contract, with Ekspan Ltd as the main contractor. Ten bearings were replaced in summer 2024 at a cost of £700k and eight in 2025 at a cost of £400k. Further bearing replacements are planned for summer 2027.