Since Iran’s 1979 Islamic revolution there have been no nightclubs or bars where young Iranians can meet and socialise. Strict families and the Islamic regime also forbid sexual relations before marriage.

Chafing at the restrictions and seeing no chance of substantive change, a new generation is escaping overzealous conservative relatives and official restrictions by heading into the wilderness.

This is not strictly about a love of nature. Once out in the country’s forests, mountains, deserts and islands, young women ditch their Islamic coverings and groups of friends dance, sing, use drugs and have sex. The younger they are, the more likely they are to challenge the Islamic Republic’s rules.

As a regular climber in the mountains around Tehran and elsewhere, I see growing numbers of groups from different social backgrounds using the great outdoors to find freedom.

Hamid Naeeini, who has been a professional guide for 16 years, says the number of camping groups has grown tenfold in the past four years, and as much as 100 times compared with a decade ago. He believes that Instagram has played a crucial role. “Gender is not an issue on the tours, even in religious areas,” he says. “People in rural areas are being affected by the changing mores.”

Fatemeh, a 19-year-old Tehrani, tells me that for the past two years she has been camping in forests “to find the reality” and escape from her “boring and repetitive” life in the capital. “We have a lot of freedom there and I even cry when I have to come back to Tehran,” she says. “Everyone is truly happy,” she says. “Having sex is totally normal. [Magic] mushrooms are nature’s gift to us. Nature is our religion.”

Many families fear that their young are running away from the reality of Iran’s social strictures. But the campers retort that the Islamic system refuses to acknowledge the reality of modern life.

For the authorities, this new method of defiance is proving difficult to control. Abbasali Soleimani, leader of Friday prayer in Kashan — a city about 250km south of Tehran surrounded by stunning deserts that are popular tourist destinations — warned this year of the “moral challenges” facing the country. “What has been happening under the name of tourism is below the dignity of the holy Islamic republic and [a betrayal of] the blood of our martyrs,” he said.

A widely circulated video of Islamic vigilantes attacking rock climbers near the historical city of Isfahan outraged the nation earlier this year. The gang argued that in their region, women and men could not do sports together.

None of this deters those determined to escape the country’s restrictions. Mehrdad, 24, is one of many unofficial tour guides using Instagram to organise trips to popular destinations such as the islands of Hengam and Hormuz in the south, as well as forests and deserts in other parts of Iran. “Young people have no other ways to have fun. I never ask them what they are smoking or drinking, or who they are sleeping with in their tent,” he says.

He explains how generational shifts have affected his tour groups. The first cohort after 1979 went through the most socially restricted period and just want to do sport, he tells me, adding that he no longer takes over 35s on his tours because they are “too serious”. The next cohort rebelled a bit, so they do “yoga and some sports” and drink alcohol, he says, while those born after 2000 look to the west on social media and are into “joints and sex”.

The gap between the concessions the Islamic republic is ready to make and the demands of young Iranians has been widening over decades, but it is quickly becoming a yawning gulf. More than 20 years of pushing in vain for reform has left many convinced that the authorities will never change, and it is a struggle to find people who still believe political, economic and social reforms can take place within the Islamic republic.

The response of many is to disengage. Fatemeh, like most pro-democracy Iranians, has no intention of voting in the June 18 presidential election. “This is only a game and I’d rather spend my time in nature than helping the authorities stifle us,” she says.