Poland competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's eighteenth appearance at the Summer Olympics, except the 1984 Summer Olympics in Los Angeles, because of the Soviet boycott. The Polish Olympic Committee sent a total of 194 athletes to the Games, 132 men and 62 women, to compete in 21 sports. Men's volleyball was the only team-based sport in which Poland had its representation in these Olympic Games. There was only a single competitor in women's taekwondo.
Hong Kong competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. It was the territory's thirteenth appearance at the Olympics and, at the opening ceremony, its team was the last to enter the stadium before the host nation because of the use of the Greek alphabet.
Czech Republic competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's third appearance at the Summer Olympics after gaining its independence from the former Czechoslovakia. The Czech Olympic Committee sent the nation's largest team to the Games since the post-Czechoslovak era. A total of 142 athletes, 80 men and 62 women, competed in 19 sports; the nation's team size was roughly denser from Sydney by one sixth of the athletes. Women's basketball was the only team-based sport in which the Czech Republic had its representation at these Olympic Games. There was only a single competitor in equestrian, artistic and trampoline gymnastics, judo, and weightlifting.
Slovakia competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's third consecutive appearance at the Summer Olympics since the post-Czechoslovak era. The Slovak Olympic Committee sent a total of 64 athletes to the Games, 48 men and 16 women, to compete in 11 sports. There was only a single competitor in artistic and trampoline gymnastics and sailing.
Belarus competed at the 2012 Summer Olympics in London, United Kingdom, from 27 July to 12 August 2012. This was the nation's fifth appearance at the Summer Olympics in the post-Soviet era. The Belarus Olympic Committee sent a total of 166 athletes to the Games, 90 men and 76 women, to compete in 20 sports.
The Netherlands competed at the 2012 Summer Olympics in London, United Kingdom, from 27 July to 12 August 2012. Dutch athletes have competed in every Summer Olympic Games since their official debut in 1908, with the exception of the 1956 Summer Olympics in Melbourne, which the Netherlands boycotted because of the Soviet invasion of Hungary. The Netherlands National Olympic Committee sent the nation's smallest delegation to the Games since 1988. A total of 175 athletes, 95 men and 80 women, competed in 18 sports.
Poland competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. This was the nation's twentieth appearance at the Summer Olympics, having missed the 1984 Summer Olympics in Los Angeles because of the Soviet boycott. The Polish Olympic Committee sent a total of 218 athletes to the Games, 130 men and 88 women, to compete in 22 sports.
Hungary competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. Hungarian athletes have competed at every Summer Olympic Games in the modern era, except the 1920 Summer Olympics in Antwerp, and the 1984 Summer Olympics in Los Angeles because of the Soviet boycott. The Hungarian Olympic Committee sent the nation's smallest delegation to the Games since 1956. A total of 159 athletes, 97 men and 62 women, competed in 18 sports.
Ukraine competed at the 2012 Summer Olympics in London, from July 27 to August 12, 2012. This was the nation's fifth consecutive appearance at the Summer Olympics in the post-Soviet era. The National Olympic Committee of Ukraine sent a total of 238 athletes, split equally between men and women, to compete in 21 sports.
Paraguay competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. This was the nation's eleventh appearance at the Olympics, except the 1980 Summer Olympics in Moscow because of its partial support to the United States boycott.
Chile competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. This nation has competed at every Olympic Games, except the 1932 Summer Olympics in Los Angeles, and the 1980 Summer Olympics in Moscow because of the United States boycott.
Cuba competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. This was the nation's nineteenth appearance in the Olympics. With baseball's removal from the Olympic program and the absence of the nation's volleyball team for the first time, the Cuban Olympic Committee sent the nation's smallest delegation to the Games since 1964. A total of 111 athletes, 66 men and 45 women, competed in 13 sports. There was only a single competitor in archery and table tennis.
Thailand competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. This was the nation's fifteenth appearance at the Olympics, except the 1980 Summer Olympics in Moscow because of its partial support to the United States boycott.
Greece competed at the 2012 Summer Olympics in London, United Kingdom, from 27 July to 12 August 2012. The Hellenic Olympic Committee sent a total of 103 athletes to the Games in London, 65 men and 38 women, to compete in 19 sports. Men's water polo was the only team event in which Greece was represented at these Olympic Games.
Slovenia competed at the 2012 Summer Olympics in London, United Kingdom. This was the nation's sixth consecutive appearance at the Summer Olympics. The Slovenian Olympic Committee sent the nation's third-largest delegation ever to the Games. A total of 65 athletes, 28 men and 37 women, competed in 15 sports. For the first time in its Olympic history, Slovenia was represented by more female than male athletes. Slalom kayaker and multiple-time world champion Peter Kauzer was the nation's flagbearer at the opening ceremony. The London Games also featured Slovenia's Olympic debut in triathlon.
Venezuela competed at the 2012 Summer Olympics in London, from July 27 to August 12, 2012. This was the nation's seventeenth consecutive appearance at the Olympics, since its debut at the same host city in 1948. Celebrating the anniversary of the nation's Olympic debut, the British Embassy in Caracas invited former track cyclist Julio César León to travel back to the United Kingdom, and revisit his memories as the first Venezuelan athlete in history to compete at the games.
The United States of America (USA) competed at the 2004 Summer Olympics in Athens, Greece. 533 competitors, 279 men and 254 women, took part in 254 events in 31 sports.
Hong Kong competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. This was the territory's sixteenth appearance at the Summer Olympics, since its debut as a British colony in 1952.
Hong Kong competed at the 2020 Summer Olympics in Tokyo, Japan, marking the territory's seventeenth appearance at the Summer Olympics since its debut as a British colony in 1952. More medals were won at the 2020 Summer Olympics by athletes representing Hong Kong than ever before, and Hong Kong also won its first gold medal since the handover back to China.
Trinidad and Tobago competed at the 2020 Summer Olympics in Tokyo. Originally scheduled to take place from 24 July to 9 August 2020, the Games were postponed to 23 July to 8 August 2021, due to the COVID-19 pandemic. It was the nation's eighteenth appearance at the Summer Olympics, although it previously competed in four other editions as a British colony, and as part of the West Indies Federation.
