The announcement that Iran's only female Olympic Olympic medalist, Kimia Alizadeh, will retire is the latest in a series of high-profile nationality changes among the country's top athletes.
The defects were responsible for various reasons and for many different sports. Here are some of the most important ones.
Alizadeh made history when she competed at the Rio Olympics in Taekwondo in 2016.
At just 18, she beat Sweden's Nikita Glasnovic 5: 1 in the battle for bronze in the -57 kg category, making her the first Iranian woman to win an Olympic medal.
But after this success, she felt that the country's authorities were using her success as a propaganda tool.
At 21, she disappeared last week and there are rumors that she wants to settle in the Netherlands.
Although she hasn't confirmed where she is, she announced in an Instagram post that she left Iran because she didn't want to be part of "hypocrisy, lies, injustice, and flattery".
"I wore whatever they told me and repeated whatever they ordered. I repeated every sentence they ordered. None of us matter to them, we are just tools," she wrote.
She has described herself as "one of the millions of oppressed women in Iran".
Shohreh Bayat, Mitra Hejazipour and Alireza Firouzja
As significant as Alizardeh's defect is, it's not even the first major Iranian sports defect of 2020 – less than two weeks a year.
Two leading figures in Iranian chess, Shohreh Bayat and Mitra Hejazipour, were expelled for removing their hijab from competitions outside the country. This action is considered a violation of Iran's Islamic dress code.
Bayat is an international chess referee – Asia's only Class A referee – and was previously the first woman to be the general secretary of an Iranian sports association. She said she would not return to Iran after photos were posted that showed that she did not wear a mandatory headscarf during the Shanghai Women & # 39; s World Championship 2020 games.
When the photos first appeared, Bayat's father said her headscarf had accidentally dropped off. But later they showed pictures without it in other games. Nigel Short, vice president of the International Chess Federation (Fide), posted a photo on Twitter that Bayat is "a great ambassador for her country", and Bayat has tweeted it again.
Her father now says that she is "concerned about continuing her activities in Iran" and is trying to continue in another country.
Meanwhile, on January 2nd, the Iranian Chess Federation expelled experienced chess master Mitra Hejazipour for removing her scarf during the World Championship in rapid and blitz chess in Moscow.
Hejazipour, who said that she would now compete privately and live in France, was informed that "she no longer has a place in the Islamic Republic's national team."
Meanwhile, at the end of 2019, the world's second junior player, Alireza Firouzja, competed under the Fide flag instead of the Iranian one.
For political reasons, Iran had a general ban on all athletes who compete against the Israeli opposition. Iran does not recognize the State of Israel.
However, since this ban violates the rules of most international sports associations, it has put several athletes in a difficult situation in competitive situations – especially sports in which both Iran and Israel have talents such as wrestling and judo.
For obvious reasons, the competition rules generally insist that athletes cannot choose who they compete against.
Competitors, under great pressure from the Iranian authorities, had to intentionally lose fights if a win resulted in them facing an Israeli.
This was the case, for example, with wrestler Alireza Karimi-Machiani, who dominated against the Russian Alikhan Zhabrailov at the 2017 U23 World Championships.
In the middle of the fight, Karimi-Machiani's coach Hamidreza Jamshidi learned that another fight was over and an Israeli would face Karimi-Machiani if he won.
So the trainer called Karimi-Machiani that he had to lose.
Karimi-Machiani was suspended for six months and Jamshidi for two years.
This prompted the head of the Iranian Wrestlers Association to resign, saying, "Forcing an athlete to accept defeat or walking around all night to seek a doctor's letter is not correct."
Saeid Mollaei became 2018 world judo champion in the category -81 kg. In defending his title in Tokyo in 2019, he was asked to end his game against Russian Olympic champion Khasan Khalmurzaev.
There were familiar reasons – to avoid the prospect of facing an Israeli, in this case Sagi Muki.
But Mollaei declined.
He continued to fight and lost to Belgian Matthias Casse in the semifinals (Muki would beat Casse and become the new champion).
After his actions, Mollaei expressed his fears for the safety of his family.
"I'm a fighter," he said at the time. "I want to participate wherever I can. I live in a country whose law does not allow me. We have no choice; all athletes have to stick to it."
"Even though the authorities in my country told me that I can return without any problems, I'm afraid of what could happen to my family and myself."
Instead of punishing Mollaei who did not return to Iran and instead moved to Europe, the International Judo Federation banned Iran from all competitions.
The ban remains.