Organisers are saying that some 160,000 people are expected to attend Brighton and Hove for the 25th annual Pride event today.
The parade, including dance troupes, drag queens and campaigning groups and other organisations, will start at Hove Lawns.
The colourful procession, starting at about 11:00 BST, will arrive in Preston Park a couple of hours later.
Road closures will affect bus routes and other traffic in the area.
In previous years, the parade has set off from Madeira Drive.
The LGBT parade, on the theme of Carnival of Diversity, will make its way from Hove Lawns, along King’s Road before joining the previous route of West Street, North Street and London Road.
Paul Kemp, the director of Pride Brighton, said:
It’s a celebration and it brings in a lot of people from all over the world. Economically, it’s very good for the city and brings in £3.5m. Behind the celebrations it highlights LGBT campaigns all over the world. There’s a long way to go globally to bring about equality.”
On Thursday, six people were injured in a stabbing at the Gay Pride parade in Jerusalem.
Peter Kyle, MP for Hove and Portslade said:
Pride is many things to many people. There are people who are straight who have got families who go along to celebrate the diversity of our city.”
Brighton DJ Fatboy Slim will be playing in the Wild Fruit dance tent in Preston Park, and the cabaret tent will be hosted by Lola Lasagne.
Other acts appearing include The Human League, Ruby Rose and Ella Henderson.