The race organisers confirmed last night that the changes for Sunday’s event were necessary following their decision to respond to runners’ requests to move the event from the June Bank Holiday Monday.

Following consultation with parish priests, gardaí, and city council traffic managers; marathon organisers have changed this year’s route, which in previous years ran close to some 14 city churches, to take runners away from these areas in a bid to avoid congestion with Mass-goers.

Race director, Jim O’Donovan, said the main changes are around St Mary’s Church on Pope’s Quay, near the Church of the Descent of the Holy Ghost at Dennehy’s Cross, and the Church of the Assumption in Ballyphehane.

The topography of city restricted race route options to the flat and narrow east-west valley, he said.

“We would have liked to take the course well away from all the churches, but we just couldn’t do it. We examined a lot of options and we think we have a route now which will minimise disruption as much as possible,” he said.

The new 26.2-mile route has been measured and certified by John Quigley, of Eagle AC, and the marathon is accredited by the Association of International Marathons.

Mr O’Donovan said that moving the event to Sunday, like other cities have done, has resulted in an increase in race numbers, with up to 7,500 people taking part — 1,400 in the full marathon, 2,600 in the half marathon, and 700 teams of five in the relay event.

“We would like to apologise in advance for the inconvenience which will be caused by the marathon. But it is just one day in the year. It is an important social and economic event for the city and I would ask people to support the runners, many of whom are running for good causes,” he said.

He also confirmed that the start of the half marathon has been moved to Monahan Road after a blunder at the start of last year’s event led to some 200 runners taking a wrong turn, adding half a mile to their race.

The marathon and first leg of the team relay starts on St Patrick’s St at 9am. The half marathon starts on Monahan Rd at 10.45am.

Around 500 volunteers, including 240 stewards, 120 medical and first aid personnel, backed by up to 100 gardaí, will be on duty throughout the day.

The marathon is one of several events taking place across the Bank Holiday weekend:

The Cork Harbour Festival kicks off with a “boats and bites” event at the Bonded Warehouses at the Port of Cork on Saturday, daily tours of Spike Islands, stand-up paddling (SUPing) at the Lee Fields, kayaking and water trampolining at Aghada Pier and the Cork Harbour Cycle on Monday. The landmark Roche’s Point lighthouse at the mouth of Cork Harbour will open to the public for the first time on Sunday.

The second Soul in the City festival, a food and music event in Cork’s Victorian Quarter around MacCurtain St, Coburg St and Bridge St, takes place across the weekend.

The 20th Innishannon Steam and Vintage Rally, which has attracted more than 1,600 entries, will take place on a 38-acre site one mile from Innishannon village. The event has raised some €1.34m for the Irish Cancer Society over the years.

Ballycotton will host its Seafood and Shanty festival, with fish specials, music and a family fun day on the pier on Sunday from 2pm to 5pm.

And in Mallow, the team at Ballyhass Lakes will host a summer party on Sunday to mark the official launch of their new wipeout-style aquapark — a huge floating inflatable playground featuring two giant slides, a trampoline, and a climbing wall, as well as hosting the first stop of the Industry Wakeboarding Grassroots tour, featuring some of the best of the extreme sport’s exponents in Ireland.

Meanwhile, the Irish Coast Guard and the RNLI are urging people to be careful in and on the water or along the coastline over the weekend: “If you do get into trouble or see someone else in difficulty, call the Coast Guard on Marine VHF channel 16 or dial 112 and ask for the Coast Guard.”

Road closures start at 8am

Road closures start at 8am. The marathon starts at 9am on St Patrick’s Street, which will be closed until 6pm.

Delays are expected around Wilton Road and Western Road from 9am to 3pm.

The South Ring Road (N40) will take most traffic diverted from the city centre.

The Jack Lynch Tunnel will remain open all day with lane restrictions in place between 8am and 1pm.

Northbound traffic should use the Jack Lynch Tunnel for the Dublin road or the Ballincollig link road at Poulavone, via the Anglers Rest, Leemount and Blarney, for Mallow and Limerick.

Southbound traffic should use the North Ring Road to the Jack Lynch Tunnel.

The Lower Glanmire Road will be open outbound only from Silversprings to the Jack Lynch Tunnel.

The Carrigrohane Straight Road will be closed inbound from 10am to 5pm. It will open outbound from 11.30am to 2pm.

Access to the city centre is via the South City Link which will be open all day with lane restrictions from 8am to 1.30pm.

After 11am, vehicles will be able to travel over St Patrick’s Bridge to MacCurtain St.

From 2pm, all city centre bridges will be open except North Gate Bridge (Griffiths Bridge).

The Lower Glanmire Road will be closed inbound from 8am to 2pm.

The Midleton-Cork Road from Dunkettle Interchange will be closed inbound from around 8am to 2pm.

Rail passengers using Kent Station between 8am and 11am will have to walk from Brian Boru Bridge or from the Summerhill North Junction with the Lower Glanmire Road to the station.

Irish Rail has laid on extra early morning commuter trains from Cobh and Midleton to Kent Station.