The group of men and women were stopped for wearing inappropriate clothes, the Young Journalists Club said.
A member of Golestan Province's Crime Prevention Unit was reported as saying that the yoga teacher was among the arrested, and had been referred to the regional prosecutor.
It is claimed the man teaching the class had advertised it on social media and that he did not have a license to teach.
Justice department official Massoud Soleimani told Arab News they were arrested for wearing 'inappropriate outfits' and had 'behaved inappropriately'.
He also revealed that the residence where the arrests took place has been monitored for some time beforehand.
Mixed-sex sports are illegal in Iran, however yoga is legal so long as classes are single-sex and the teacher is licensed to teach it.
Yoga schools in Iran advertise their services online and publicize that they have instructors.
In 2017, Ali Majdara, president of Iran's Sports For All Federation announced a ban on activities that use 'rhythmic motions' and 'dance' including Zumba.