About 55,000 gathered in the chill Canberra pre-dawn at the Australian War Memorial for the national service, well below the 120,000 who turned out in 2015 for the 100th anniversary of the ill-fated landings.
Memorial director Brendan Nelson said Anzac Day was not about war, but about love and friendship.
"102,700 Australians are named on the roll of honour. Like us each had only one life, one life to serve others and our nation. They chose us," he said.
Victoria Cross recipient Ben Roberts-Smith said he believed interest in the Anzacs was far from waning.
"It is probably across the board increasing. Importantly the next generation of Australians acknowledge that sacrifice and have been taught that is what we must do, moving forward as a country," he told reporters.
Sydney's service was marred by news that a .
NSW Premier Mike Baird described the arrest as disturbing, but urged people to still commemorate the day.
"My strong encouragement is if you are intending to go (to an Anzac service), go," he told reporters after the Martin Place dawn service.
Lieutenant Colonel John Moore warned the crowd, estimated at more than 20,000 by the RSL, that some of Sydney's war memorials had been "desecrated" by developers.
NSW Premier Mike Baird and Federal Senator Concetta Fierravanti-Wells lay wreaths during the Anzac Day dawn service in Sydney, Monday, April 25, 2016. Source: AAP
Prime Minister Malcolm Turnbull was up early for the dawn service at the North Bondi RSL before heading to Canberra, while Opposition Leader Bill Shorten joined about 45,000 people in the dark at Melbourne's Shrine of Remembrance.
"Today we remember courage and unity and think about self worth and decency in the face of fear," MC Peter Meehan told the Melbourne crowd.
In Adelaide, 8000 people at the city's war memorial were told that war veterans needed proper care, given their sacrifices and the scars - physical and emotional - many still bear.
Ian Smith, SA Anzac Day committee chairman, said politicians bore a great responsibility when sending young people to war.
"A responsibility that includes caring properly for them when they return home," he said.
Governor Paul de Jersey echoed that message to the 25,000 at Brisbane's Shrine of Remembrance, with a reminder to show sensitivity to modern-day soldiers carrying the psychological scars of service.
"We must not forget veterans whose war wounds are not readily visible," he said.
Crowds gather around the eternal flame at the Shrine of Rememberance for the Anzac Day dawn service in Melbourne Source: AAP
In Darwin, a special plaque was laid during a service at the Cenotaph for Northern Territory soldier Scott Palmer, who was killed in Afghanistan in 2010.
Large crowds also turned out in Hobart and Perth, where 40,000 people gathered at Kings Park alongside Premier Colin Barnett, Foreign Minister Julie Bishop and former East Timor prime minister Xanana Gusmao.
They heard Wing Commander Peter Kershaw tell of how the ethos that developed in the trenches of Gallipoli and the Western Front sustained and inspired those now wearing the Australian uniform.
Overseas, rain greeted Australians and New Zealanders as they trooped in to the Anzac commemoration site to camp out overnight for the service on Turkey's Gallipoli Peninsula.
Governor-General Peter Cosgrove will attend the service at Villers-Bretonneux in France.
An ex-serviceman waches on during the Anzac Day dawn service in Sydney, Monday, April 25, 2016. Source: AAP
