[1] Australia is one of only five countries to have sent athletes to every Summer Olympics of the modern era, alongside Great Britain, France, Greece, and Switzerland.

Injuries, mental health concerns, family reasons and positive COVID infections caused several officially selected athletes to withdraw and be replaced where possible.

[15] On 6 March 2020, Rio 2016 bronze medallists Ryan Tyack and Taylor Worth, with David Barnes making his Olympic comeback after his debut in Athens 2004, were officially named to the men's archery team for the Games, based on their individual results at the four-part selection trials.

[18] The artistic swimming squad, highlighted by Rio 2016 Olympians Hannah Cross, Emily Rogers, and Amie Thompson, were officially selected to the Australian roster for the Games on 26 February 2020.

[19] Initially set to compete in both duet and team events at the rescheduled Games, Rio 2016 Olympian Rose Stackpole officially announced her retirement from the sport in August 2020.

Australian athletes further achieved the entry standards, either by qualifying time or by world ranking, in the following track and field events (up to a maximum of three athletes in each event):[21][22] On 19 August 2020, national champions Stewart McSweyn and Jessica Hull in the long-distance running, race walkers Jemima Montag and Rio 2016 bronze medallist Dane Bird-Smith, and reigning world javelin throw champion Kelsey-Lee Barber were the first track and field athletes officially selected to the Australian squad for the rescheduled Games.

[27] Australia men's basketball team qualified for the Olympics by advancing to the second round and securing an outright berth as the highest-ranked Oceania squad at the 2019 FIBA World Cup in China.

[39] They must also compete at the Australian Open and in two trials of the Oceania Championships, both held in Penrith, New South Wales, to assure their selection to the nation's Olympic slalom canoeing team.

[42] At the end of the two-stage selection trials, fourteen sprint canoe and kayak paddlers were officially named to the Australian team on 27 March 2020, with London 2012 gold medallist Murray Stewart in the men's K-4 500 metres making his third consecutive trip to the Games.

[48] Qualification legend: FA=Gold medal final; FB=Bronze medal final Australian mountain bikers qualified for one men's and one women's quota place each into the Olympic cross-country race, as a result of the top-two finish vying for the men's qualification under the elite category at the 2019 UCI World Championships in Mont-Sainte-Anne, Canada, and the nation's twenty-first-place finish for women, respectively, in the UCI Olympic Ranking List of 16 May 2021.

Australian equestrians qualified a full squad in the team dressage competition by receiving a spare berth freed up by host nation Japan, as the top-ranked nation from Southeast Asia and Oceania, not yet qualified, at the 2018 FEI World Equestrian Games in Tryon, North Carolina, United States.

Additionally, the country's eventing and show jumping teams qualified for the Games by virtue of a top-six finish each in the same tournament.

[54] Originally-selected Chris Burton later withdrew, causing Tinney to step in, and granting Kevin McNab and Don Quidam to become the new traveling alternates.

[58] Key: Australia men's national field hockey team qualified for the Olympics by beating New Zealand with a unanimous 3–0 for a gold-medal victory at the 2019 Oceania Cup in Rockhampton, Queensland.

Key: For the first time in twelve years, Australia men's football team qualified for the Games by winning the bronze medal and securing the last of three available berths of the 2020 AFC U-23 Championship in Thailand.

American-based Tyson Bull secured one of the two places available for individual-based gymnasts, neither part of the team nor qualified through the all-around, in the horizontal bar exercise, while two additional berths were awarded to the Australian female gymnasts, who participated in the women's individual all-around and apparatus events at the 2019 World Championships in Stuttgart, Germany and at the 2021 Oceania Championships in Gold Coast, Queensland.

Tsuneari Yahiro will be competing in men's kumite 75 kg, after World Karate Federation give him continental representation quotas.

[79][80] Meanwhile, the women's quadruple sculls boat was awarded to the Australian roster with a top-two finish at the 2021 FISA Final Qualification Regatta in Lucerne, Switzerland.

[87][88][89] On 20 September 2019, the Australian Olympic Committee announced the first set of sailors selected for Tokyo 2020, namely Rio 2016 silver medallists and defending world 470 champions Mathew Belcher and William Ryan and world's current top-ranked Laser sailor Matthew Wearn.

[90] The skiff crews (49er and 49erFX), highlighted by Ryan's sister and fellow Rio 2016 Olympian Jaime Ryan, were named to the sailing team on 27 February 2020, while Nacra 17 cousins Jason Waterhouse and Lisa Darmanin were set to defend their Rio 2016 podium finish at the Enoshima regatta, after being selected four days later.

[91][92] Laser Radial sailor Mara Stransky joined the sailing roster on 19 March 2020, followed by the women's 470 crew (Nia Jerwood & Monique de Vries) over a year later.

[93][94] Finn yachtsman and Rio 2016 Olympian Jake Lilley rounded out the sailing selection for the rescheduled Games on 21 April 2021.

[95] M = Medal race; EL = Eliminated – did not advance into the medal race Australian shooters achieved quota places for the following events by virtue of their best finishes at the 2018 ISSF World Championships, the 2019 ISSF World Cup series, and Oceania Championships, as long as they obtained a minimum qualifying score (MQS) by 31 May 2020.

[96] On 17 April 2020, the Australian Olympic Committee officially announced a roster of fifteen shooters selected for the rescheduled Olympics, with pistol ace Daniel Repacholi leading them to his remarkable fifth Games, Kazakh import Dina Aspandiyarova to her fourth, and rifle marksman Dane Sampson to his third.

[109] On 22 July 2020, Australian Olympic Committee nominated Rio 2016 Olympians David Powell and Chris Yan, returning Olympian Stephanie Sang from Beijing 2008, and rookie Michelle Bromley to compete in their respective singles tournaments for Tokyo 2020, following their top two finish at a national selection meet in Melbourne.

[111][112] The main qualifying criterion will be players' positions on the ATP and WTA ranking lists published on 14 June 2021 after the 2021 French Open.

Australia qualified six triathletes for the following events at the Games by finishing among the top seven nations in the ITU Mixed Relay Olympic Rankings and the calculation of quotas following the 2021 World Triathlon Cup.

Baseball Australia Chief Executive Glenn Williams said the withdrawal was due to protocols around quarantining as a result of the COVID-19 pandemic.