Using some of the Capital's most prestigious hotels has become a "fashion" among sex workers, with the venues being chosen because of their tight security, including CCTV.
Other hotels being used for prostitution, as at the Balmoral unknown to their management, include the Macdonald Holyrood, next to the Scottish Parliament, the Royal Mile's Radisson Blu and the Ramada Jarvis Mount Royal on Princes Street.
Upmarket escorts tend to book overnight rooms, at a cost of up to 500 at the Balmoral, to be discreet and avoid raising the suspicion of hotel staff.
Charging up to 200 an hour, some will meet a string of clients in a day, while others charge up to 1500 for a 24-hour session.
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The charity Scotpep estimates that there are around 700 women working as prostitutes in the city, although not all will be working regularly at any one time.
Most work from saunas and private flats, with around 80 to 100 selling sex from the streets, but growing numbers regularly use hotels. The rise of the internet, and the ease with which individual prostitutes can advertise their services, has encouraged many more to work alone.
While only a handful worked regularly from hotels a few years ago, there are now thought to be dozens doing so.
One sex industry source said: "More and more women are working from hotels rather than private flats. They feel safer and it's also more convenient.
"When they use a private flat they have to rent it out and that can mean paying for longer stays than they need. There's also the issue of neighbours finding out.
"Some of the women only come to Edinburgh for a few days as part of national 'tours' so it suits them to use a hotel."
The women involved are not necessarily breaking the law as it is not illegal in Scotland to sell sexual services, but they could be prosecuted for operating a brothel if more than one was working together from a particular hotel, or for other related offences.
One upmarket escort, whose working name is Helena, said she regularly uses the Balmoral to meet clients, and told the Evening News the practice was widespread.
The 30-year-old brunette said: "I have known of ladies who have been asked to leave because they have a high turnover of clients, are too noisy or are not discreet. But if you dress smartly and do not cause a fuss, it isn't a problem."
Another high-class student prostitute, a 20-year-old blonde, who we agreed to identify only as Anna, added: "I rely on hotels to conduct my business. I regularly use central spots such as the Radisson. I've never been stopped or questioned, but I think that's down to your discretion. It really does depend on how you present yourself and the kind of clientele you keep.
"I have friends who work as escorts and they also regularly use hotels. It's the safest place for us to work. Nobody wants to get caught dealing with an escort so a client isn't going to act up in what is essentially a public place."
Ruth Morgan Thomas, a board member of Scotpep, which provides advocacy support for prostitutes in Edinburgh, said that the sex industry was becoming increasingly dangerous as the rise of the internet, the end of the city's tolerance zone and the introduction of anti-kerb crawling legislation in Scotland had changed working patterns.
"Women in the sex industry are increasingly working on their own, often from private accommodation and using the internet," she said. "That means they are more isolated and the work is more dangerous.
"Women working in saunas are in groups and that offers a degree of protection. If someone is working from private accommodation they are more vulnerable."
Independent Lothians MSP Margo MacDonald said: "For many people, the morality questions surrounding prostitution leaves them unable to consider the safe management of those who work in it. We have to be realistic that the selling of sex is going to happen so we need to support ways to make it safer for the women involved in this practice."
The Balmoral and Radisson Blu declined to comment, while a spokeswoman for the Ramada Jarvis said they did not wish to comment other than to say they did not believe the hotel has been used by prostitutes.
Chris Wayne-Wills, regional director with Macdonald Hotels, said: "We were not aware of this situation and it's something we are now looking into."