President Karol Nawrocki will award state honours at the Presidential Palace before attending the main ceremony at Piłsudski Square in Warsaw at midday, where he will give a speech and promote several army officers to the rank of general.
He will be accompanied by First Lady Marta Nawrocka.
Earlier, on Wednesday morning, the president and other officials laid wreaths at monuments to the "Fathers of Independence," including Polish statesmen Józef Piłsudski and Ignacy Jan Paderewski.
Prime Minister Donald Tusk will be in Szczecin for the christening and flag-raising of the ferry Bursztyn Unity.
He has said it will show Poland and the world that the country is returning to the Baltic and the seas on a large scale, calling it "a beautiful gift" to Poles for the anniversary.
In the afternoon, the Independence March will take place in Warsaw under the slogan "Polak w Polsce gospodarzem" ("A Pole as host in Poland").
Organiser Bartosz Malewski said he expected a record turnout and "would not be surprised" by half a million people.
Nawrocki has said he will join the march "as every year."
The annual demonstration has long been a source of controversy over nationalist rhetoric, and this year's slogan has further fueled debates surrounded by anti-immigration sentiment and political divisions.
Politicians from the biggest opposition grouping Law and Justice (PiS), including party leader Jarosław Kaczyński, as well as the Confederation party and the Rozwój Plus association, have also said they will take part.
In Kraków, where six people were killed and more than ten injured in a shooting attack last Saturday, the day will be marked more quietly.
Cardinal Grzegorz Ryś will lead a Mass at Wawel Cathedral, and the military ceremony at the Tomb of the Unknown Soldier will be scaled back, with no changing of the guard, roll call of remembrance, gun salute or military parade.
Sejm Speaker Włodzimierz Czarzasty will travel to the city to lay a wreath on the grave of Ignacy Daszyński, a speaker of parliament in interwar Poland.
He will also light a candle at the site of the attack on the Main Square and sign a book of condolence.
The holiday marks the day in 1918 when Poland’s Regency Council handed the supreme command of Polish forces to Józef Piłsudski.
Established in 1937, the holiday was abolished in 1945, restored in 1989, and is currently a public holiday.
(ał)
Source: PAP, IAR