The Woodbridge 10k Round the Town and Junior races return on Sunday, May 21, with runners from around the county and further afield taking part.
Around 900 runners will take part, and, as a result, full and partial road closures will be in place throughout some of Sunday.
New Street and St John's Hill will close from 11.45am to 12.15pm, with Burkitt Road, Angel Lane, Queens Head Lane, Thoroughfare, Church Street, Market Hill, Seckford Street, Drybridge Hill and Theatre Street closed from midday to 1.45pm
Meanwhile, Ipswich Road, Station Road, Quayside and Lime Kiln Quay Road will be one-way only towards the Duke of York.
A letter to local residents and businesses states:"So that the runner are safe, we have to close some roads temporarily.
'The period of most traffic disruption will be between midday and 1.15pm, and we hope that motorists will be able to avoid driving in central Woodbridge or using Ipswich Road/Station Road between these times.
'We hope you will be able to come out and encourage the runners."
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