However, on the day of the event, female participants from around the world were shocked to learn that an Iranian government order required them to run apart from men and off the streets in a nearby stadium. They were also only allowed to participate in the 10K race (the marathon included 10K, 21K and 42K runs).
In the weeks leading up to the event, Iran's track and field federation provided several confusing updates on the matter.
Three weeks before the marathon, female participants were told via email that they were banned from taking part. But after negotiations with authorities, news came out that they would be allowed to participate.
A week before the event, non-profit Free to Run shared the news in a Facebook post and said that they were "encouraged" by reports on women being allowed to run.
This is the second race organized in Iran by Dutch Sebastiaan Straten, but the first one where women could officially participate.
Speaking to the Washington Post, Straten said that "his event was eventually given the okay to allow its male and female entrants to run together."
Sports Minister Massoud Solanifar denied these claims, stating that "from the start, there was no chance the competition would be mixed."
In recent years women in Iran have been fighting against the strict rules imposed on them, especially when it comes to sports.
Women defy the order
In defiance of the order many women ran the full 42-kilometer race alongside men, including Free to Run ambassador Mahsa Turabi and Chinese runner Wu Juan.
Some were quickly kicked out, others even risked arrest, but their move sent a powerful message to everyone.
While several eventually decided not to take part in the event, a few organized their own “secret” marathon in the hilly local Beheshte Madaran park. They ran outdoors before joining the official 10K race for women.
In the first race Straten organized in the southern Iranian city of Shiraz in April last year, women were banned from running altogether.
This led Masoumeh Torabi and Elham Manoocheri to run on the sidelines of the marathon in protest of the continued discrimination against women in the country.
This isn't the first time women in Iran defy discrimination
In recent years many Iranian women have been fighting against discrimination they face in sports. Some, including chess player Dorsa Derakhshani and motorbiker Behnaz Shafiei overcame limitations imposed on them and are now setting a bright example for others to follow.