Lambeg drumming, food stalls and speeches are all planned, as thousands of people are expected to take to the streets of the city to mark 100 years since partition as part of parade organised by the Orange Order.
Thousands more spectators are set to gather to watch the parade, with a few attendees arriving as early as 9am along the route into the city centre.
The event to mark the creation of Northern Ireland in 1921 comes after the Covid-19 pandemic postponed the celebrations planned last year.
The big day has finally arrived! Wishing everyone - participants and spectators - a very enjoyable day as we celebrate the Centenary of Northern Ireland. pic.twitter.com/7Ga6ctVETo
— Orange Order (@OrangeOrder) May 28, 2022
Large crowds are set to gather at Stormont from 10am, with speeches planned at Parliament Buildings before the parade makes its way into Belfast city centre along Prince of Wales Avenue and the Upper Newtownards Road.
The Police Service of Northern Ireland (PSNI) warned ahead of Saturday that the parade will likely cause delays and diversions for motorists in and around the city.
Some shops and businesses are also expected to close early to avoid the disruption.
Grand Master of the Orange Order Edward Stevenson will be among those addressing the crowd.
Members of the Association of Loyal Orangewomen of Ireland, as well as the Junior Grand Orange Lodge of Ireland, the Royal Black Institution and the Apprentice Boys of Derry, will join the event.
The Grand Orange Lodge of Ireland Centenary Parade will take place in Belfast today at 1pm. The parade will leave Stormont at 1pm and proceed to City Hall. Diversions are in place and delays are expected. Allow extra time for your journey if you are travelling through Belfast. pic.twitter.com/mPeeL3GRd3
— Police Service NI (@PoliceServiceNI) May 28, 2022
Orangemen and women from England and Scotland are also expected to attend.
Unionist politicians are set to join the event, including Democratic Unionist Party leader Sir Jeffrey Donaldson and Ulster Unionist Party leader Doug Beattie.
Mr Beattie called the event “truly historic”.
“It was unfortunate that the Covid-19 pandemic delayed celebration plans, but it is testament to the leadership and members of the Orange Order that this parade is now proceeding.”