The border of China, Russia and North Korea. [Photo provided to China Daily]

Getting on the tour is relatively easy, he says - as long as you are Chinese. Chinese nationals can sign up through a bicycle club anywhere in China, "and with a valid passport you can get permission to join in two or three days".

Restricting the tour to members of bicycle clubs reflects the fact that it is new, and as a tourist "product" there is still room for improvement, Piao says, including with the route, which he feels at the moment is "too simple" and lacks sightseeing attractions.

"I hope we can open up more routes in the future. The key thing at the moment is that we can guarantee the safety of those who do the tour."

Sun also sees scope for more routes.

"I was born in the Northeast and am strongly attracted to the sea. To be honest, I was a bit disappointed that even though on the tour we were able to eat seafood, we did not get the chance to ride along the coast. I hope they can include a beach route soon."

Tourists entering the DPRK are prohibited from taking mobile phones and cameras with them, and Sun says he hopes such rules can be relaxed in the near future.

Han Junhong contributed to this story.