Каролина Марин

2009–2011: First international title and European Junior Champions

In 2009, she became the first Spanish badminton player to win a silver medal first, at the European Junior Championships, and also in the same year, won the gold medal at the European U-17 Junior Championships. She won her first major title at the Irish International tournament coming through the qualification stage and beating the Dutch player Rachel Van Cutsen in the final in the rubber game.

In 2011, she alongside her teammate, Beatriz Corrales, made history for the Spanish badminton, after placing two representatives of Spain in the final at the continental European Junior Championships held in Vantaa, Finland, and Marín grabbed the gold medal. She also competed at the World Junior Championships in Taipei, reaching the semi-finals, but lost to Elisabeth Purwaningtyas of Indonesia and settled for the bronze medal.

2013–2014: First Grand Prix title, European and World Champions

In 2013, she became the first Spanish badminton player to win a Grand Prix Gold title after winning the London Grand Prix Gold. In August, Marín played for the Bangalore-based team Banga Beats in the inaugural edition of the Indian Badminton League (IBL). In April, she won her first European Championships title.

On 31 August 2014, she defeated Li Xuerui of China in the World Championships women's singles final and became the first Spaniard to win a World Championship title and the third European female player to achieve the gold medal, after Lene Køppen (1977) and Camilla Martin (1999). At the age of 21, she became the youngest European that won the World Championships ever.

2015: Five Superseries title, second World Championships and World #1

In 2015, she won the All England Open, her first Superseries Premier title in her first Superseries Premier final after defeating Saina Nehwal in the final with score 16–21, 21–14, 21–7. The title propelled her to rank number 4 in the world ranking and, for the first time, no. 1 in the Superseries standing. At India Open, she had the chance to unseat Li Xuerui as the new world no. 1, however, she narrowly lost to Thai prodigy Ratchanok Intanon in a close three games at the semi-finals stage. She rose to a career-high as world no. 2 in the world ranking on 2 April.

On 5 April, Marín won her second straight Superseries Premier title, beating Olympic champion Li Xuerui for the second consecutive time at the 2015 Malaysia Open with a score of 19–21, 21–19, 21–17. In August, she defended her title at the World Championship by beating Saina Nehwal of India in 21–16, 21–19. 2015 was the golden year for Marín, where in addition to defending the World Championships title, she also won other Superseries titles such as the Australian Open, French Open, and Hong Kong Open.

2016: Olympics gold

In August, she represented her country at the Rio Olympics. She arrived at Rio as the number one seed and won a gold medal by beating India's P. V. Sindhu in the women's singles final with a score of 19–21, 21–12, 21–15. She made history by becoming the first non-Asian to win the Olympic badminton women's singles gold medal. An indoor arena in Huelva is named after her honour, with Marín herself attending the inauguration.

2017–2018: Fourth European and Third World Championships title

In 2017, Marín won the Japan Open Superseries title after beating He Bingjiao of China in the final, winning a Superseries title after almost two years. At the Hong Kong Open, which took place in late November, Marín retired to Michelle Li, losing 21–19, 13–21, 8–11, due to a hip injury that she sustained during the match. Marín later announced on Twitter and Instagram that, due to her hip injury, she would not be participating in the season-ending Dubai World Superseries Finals.

On 29 April 2018, she won her fourth consecutive European Championships title in her home soil Huelva, Spain, by beating Evgeniya Kosetskaya with a score of 21–15, 21–7 in the final. On 5 August, she won the title in the World Championships by defeating P. V. Sindhu of India in straight games 21–19, 21–10, making her the first female player in history to win three World Championships titles. In September, she won World Tour titles at the Japan and China Open.

2019–2020: ACL injury and comeback

Marín began her 2019 season with a runner-up effort at the Malaysia Masters, where she lost to Ratchanok Intanon in straight games. On 27 January, Marín suffered a ruptured anterior cruciate ligament (ACL) injury during the Indonesia Masters final against Saina Nehwal, when she was 10–3 ahead in the first games. Marín subsequently retired from the match and underwent the ACL reconstruction surgery as soon as she was flown back to Madrid the same day. She had a recovery for four months, dedicate 10 hours a day to rehabilitation between the physical and technical, with morning and afternoon physiotherapy sessions, and swimming pool work.

In September, after an eight-month break forced by the injury, Marín returned to competition at the 2019 Vietnam Open but suffered an opening round defeat to Supanida Katethong. However, she was able to bounce back and, on 22 September, she won the China Open, defeating Tai Tzu-ying in the finals with a score of 14–21, 21–17, 21–18. This was Marín's first title of the season, which she followed with the semi-finals at the Denmark Open, where she was defeated in three tight games by Nozomi Okuhara. She reached the final of the French Open next week, where she was defeated by Korean youngster An Se-young in three games 21–16, 18–21, 5–21. Her achievements in the last three tournaments succeeded in bringing her back into the world top 10 of BWF women's singles ranking. She further won Syed Modi and Italian International tournaments later in the year.

Marín started the 2020 season at the Southeast Asian tour on a positive note; reaching the semi-finals of Malaysia Masters where she lost to Chen Yufei. A week later, she then reached the final of the Indonesia Masters, where she narrowly missed the title after getting defeated from Ratchanok Intanon in three games 19–21, 21–11, 18–21. She continued her good form and thereafter reached the semi-finals of Thailand Masters, which she lost to top seed Akane Yamaguchi in a close rubber game. In February, she reached the final of her home event Barcelona Spain Masters, where she lost in an upset to rising Thai star Pornpawee Chochuwong in the rubber games 21–11, 16–21, 18–21. In March, she competed as 8th seeds in the All England Open, but stopped by the eventual champion Tai Tzu-ying in the semi-finals.

In July, Marín's father died following an accident in February. She reached the final of the Denmark Open in October for the very first time but was defeated by Okuhara in straight games.

2021–2022

Marín won the first title of the year, the Thailand Open Super 1000 event, by beating World no. 1 Tai Tzu-ying in two comfortable games. She didn't lose any game in the whole tournament. Continuing her scintillating form, she won the second edition of Thailand Open, the Toyota Thailand Open, also a super 1000 event by beating Tai yet again. In contesting her first-ever World Tour Finals final, she lost to same rival Tai in three games after failing to capitalize her lead in the final game. She won her first world tour title in Switzerland by beating reigning World champion P. V. Sindhu with a very dominating display, winning 21–12, 21–5. Marín planned to compete at the All England Open but pulled out of the competition due to an injury she suffered in the first round of the Swiss Open.

Marín made history as the first-ever player to claim five consecutive titles at the European Championships, defeating young Dane Line Christophersen in the final. She was expected to defend her title at the 2020 Tokyo Olympics but was forced to withdraw due to knee injury she suffered in June while training.

In 2022, 18 months after Marín second ACL injury, she advanced to the French Open final, but lost the match to He Bingjiao in a close rubber games.

2023: Silver medals at World Championships and World Tour Finals, Return to Top 5

Marín began 2023 at the Malaysia Open, the first Super 1000 event of the year, reaching the quarterfinals before losing to Chen Yufei in two close games. She repeated this result at the India Open, falling to Akane Yamaguchi in three games. At the Indonesia Masters, Marín defeated Hsu Wen-chi, Busanan Ongbamrungphan, Line Christophersen, and Han Yue to reach her first final in nearly two years. She faced world number two An Se-young in a three-game match lasting 80 minutes, ultimately losing.

In March, Marín reached the quarterfinals of All England Open Championship but withdrew due to injury, giving An Se-young a walkover. She returned home for the Spain Masters, reaching the semifinals before being defeated by Gregoria Mariska Tunjung in three games. Marín claimed her first title in over two years at the Orléans Masters, a Super 300 event, after defeating Beiwen Zhang in a three-game final.

In June, Marín faced world number one An Se-young in the Thailand Open semifinals, losing in straight games. The Singapore Open marked the first time in 2023 that she failed to reach a tournament quarterfinal as she lost to Supanida Katethong in the second round. However, She rebounded at the Indonesia Open, a Super 1000 event, defeating Goh Jin Wei, Yeo Jia Min, Tai Tzu-ying, and Ratchanok Intanon to reach the final. There, she lost again to Chen Yufei with an 18-21, 19-21 scoreline, mirroring their Malaysia Open match result. Marín capped off June by representing Spain at the European Games, winning her first gold medal in the tournament with a straight-game victory over Mia Blichfeldt.

Entering the World Championships taking place in Denmark as the sixth seed, Marín exceeded expectations as She defeated top-four players Tai Tzu-ying and Akane Yamaguchi en route to her fourth World Championship final. There, she lost in straight games to top-seeded An Se-young, earning a silver medal. In September, she reached the quarterfinals of both the China Open Super 1000 event and Hong Kong Open Super 500 event.

In October, Marín's strong year-to-date performance saw her return to the world number five ranking. She reached the final of the Denmark Open Super 750 event, with a notable semifinal win over Tai Tzu-ying, there she lost to Chen Yufei in straight games. This semifinal was marked by her tension with P.V. Sindhu over shuttle post-rally returns and screams, resulting in yellow cards for both players; both players later publicly apologised and reconciled. At the French Open, Marín suffered an upset loss to Aya Ohori in the quarterfinals. Further results included reaching the quarterfinals of the Japan Masters and round of 32 at the China Masters (upset by unseeded Nguyễn Thùy Linh).

Her world tour ranking of number four qualified Marín for the $2.5-million-prized year-end World Tour Finals. She won all her round-robin matches without dropping a game, including a notable victory over Chen Yufei. After defeating Chen Yufei again in a three-game, 104-minute semifinal, Marín reached her first-ever World Tour Finals final. She lost to Tai Tzu-ying in three games, earning a silver medal. Marín's total 2023 prize money of $257,335 placed her as the year's fourteenth highest-earning badminton player.

2024: All England title

Marín began 2024 by opting out of BWF tournaments in January and February, citing continued recovery from injuries. Her return to competition was at the European Men's and Women's Team Badminton Championships as part of the Spain's national team. Despite Marín's individual victories over Kirsty Gilmour and Line Kjærsfeldt in the semifinals and finals, respectively, her team finished as runners-up in the tournament.

In March, Marín experienced an early exit at the French Open, losing to Beiwen Zhang in the opening round. However, she rebounded at the prestigious All England Open Super 1000 event. En route to the final, she had notable victories over Wang Zhi Yi, Chen Yufei, and Tai Tzu Ying. In her final match against Akane Yamaguchi, Marín secured a hard-fought victory in the first game (26-24) and was leading 11-1 in the second game when Yamaguchi retired due to injury, granting Marín her second All England title after a nine-year interval. In the following week, Marín extended her winning streak by clinching her second title of the year, the Swiss Open Super 300 title, thus becoming the oldest women’s singles player in 16 years to achieve this feat, following Zhang Ning's triumph in 2007. In the quest for her second Swiss Open title, she defeated Gregoria Mariska Tunjung in a hard fought final, with a scoreline of 21-19, 13-21, 22-20.