Equatorial Guinea competed at the 2004 Summer Olympics in Athens, which was held from 13 to 29 August 2004. The country's participation at Athens marked its sixth appearance in the Summer Olympics since its début at the 1984 Summer Olympics. The delegation included two athletics competitors: Roberto Mandje and Emilia Mikue Ondo in the long and middle distance disciplines respectively. Mikue Ondo was selected as the flag bearer for the opening ceremony. Both athletes did not advance further than the first round of their respective events with Mandje failing to make the start of the men's 3000 metres steeplechase.
José Luis González Sánchez is a Spanish former middle-distance runner. He represented Spain at the Olympics on three occasions with his best performance being a semi-final run in the 1500 m in 1980.
Bayron Efrén Piedra Avilés is an Ecuadorian middle distance and long-distance runner.
Eyawomano Doreen Amata is a female track and field athlete from Nigeria who specialises in the high jump event.
Luis Alberto Marco Contreras is a Spanish middle-distance runner. He specializes in the 800 metres.
Francine Niyonsaba is a Burundian runner who specialized in the 800 metres and shifted to longer distances in 2019. She was the 2016 Rio Olympics silver medalist in the women's 800 metres. Her silver medal was the first Olympic medal for Burundi since 1996. Niyonsaba won a silver in the event at the 2017 World Championships.
Sibusiso Bruno Matsenjwa is a sprinter from Eswatini. He competed in the 200 metres at the 2012 and 2016 Olympics, but failed to reach the finals. He broke the national record on both occasions and served as the flag bearer for Eswatini during the opening ceremony in 2016. Matsenjwa holds national records over 100–400 m distances. He represented his country at three outdoor and three indoor world championships. Sibusiso also competed at the 2018 Gold Coast Commonwealth Games.
Musaeb Abdulrahman Balla is a Sudanese-born Qatari middle-distance runner competing primarily in the 800 metres. He represented Qatar at the 2012 Summer Olympics as well as two outdoor and three indoor World Championships.
Luiza Gega is an Albanian middle- and long-distance runner who specialises in the 3000 metres steeplechase since 2016. She won the silver medal in the event at the 2016 European Championships, and a gold in 2022 setting the championship record in the process. Her silver was the first ever Albania’s European medal, while her gold was the first ever title for the country at the European Athletics Championships.
Burundi competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. This was the nation's sixth consecutive appearance at the Summer Olympics.
Eritrea competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. It was the nation's fifth consecutive appearance at the Summer Olympics.
Djibouti competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. The nation's participation marked its eighth appearance at the Summer Olympics. Djibouti did not field any athletes at the 2004 Summer Olympics in Athens.
Noélie Ditchakou Yarigo is a middle-distance runner from Benin who competes primarily in the 800 metres. She represented her country at the 2016 Rio and 2020 Tokyo Olympics.
Charlotte Wingfield is a Maltese sprinter who competes on behalf of the Republic of Malta.
Esther Guerrero Puigdevall is a Spanish middle-distance runner competing primarily in the 800 metres. She won two medals for the mixed relay at the European Cross Country Championships.
Erick Rodríguez is a Nicaraguan middle-distance runner competing in the 1500 metres and 3000 metres steeplechase. He represented his country at the 2015 World Championships and 2016 World Indoor Championships without advancing from the first round.
Andorra competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. This was the nation's eleventh consecutive appearance at the Summer Olympics.
The Maldives competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. This was the nation's eighth consecutive appearance at the Summer Olympics. The delegation included two track and field athletes: Hassan Saaid and Afa Ismail, as well as swimmers Ibrahim Nishwan and Aminath Shajan. Both Shajan and Ismail were returning competitors from the 2012 London Olympics, with the former leading the Maldivian squad as the flag bearer in the opening ceremony. The Maldives, however, has yet to win its first ever Olympic medal.
Alex Amankwah is a Ghanaian middle-distance runner specialising in the 800 metres. He attended college and competed in athletics at the University of Alabama, where he set a school record and was a First Team All-American in the indoor 800 metres. He qualified for the 800 metres at the 2015 World Championships in Beijing, China but was unable to compete due to visa issues. He also represented Ghana in the 4 × 400 metres relay at the 2015 African Games.
Halimah Nakaayi is a Ugandan middle-distance runner who specialises in the 800 metres. She is the 2019 World Champion at the event and won the bronze medal at the 2022 World Indoor Championships. Nakaayi is the current Ugandan record holder for the 800 m both outdoors and indoors, and also for the 1000 metres.
Andorra 
