More than 12,000 runners are ready to start the Grand Brighton Half Marathon, organised by the Sussex Beacon.
While the race is taken seriously by a core of elite runners, many will be raising money for good casuses, including the Beacon.
The race, in its 29th year, is the HIV charity’s biggest annual fundraising event. But many will be raising money for other good causes including the Chestnut Tree House children’s hospice.
Park and ride sites were due to open at 7am, with the race village and help desk opening at 7.30am and road closures in place from 2am in Madeira Drive and 8.15am elsewhere.
With the race village due to close at 2.30pm, the organisers expect all local roads to have been reopened before this time, except Madeira Drive, which should reopen by 7pm.
The 13.1-mile main race starts at 9.30am but there will also be youth races, a wheelchair race and corporate relay.
The course starts and ends in Madeira Drive, taking in a seafront stretch to Ovingdean, a leg towards St Peter’s Church, and a seafront stint to Hove Lagoon and back.
The weather is expected to warm and dry for February with a light south easterly wind.
Bus bosses have warned passengers to expect some delays and disruption.
The road closure schedule is expected to be
2am to 7pm – Madeira Drive
8.15-11:40 – Old Steine, Marlborough Place, Gloucester Place, Grand
Parade and Pavilion Parade
8.15 to 11.15am – Marine Parade and Marine Drive
8.15 to 1.30pm – King’s Road to West Street (westbound and eastbound lanes)
8.15 to 1.30pm – King’s Road and Kingsway (westbound lane only)