Wigan's tanning salons have received praise from council bosses as part of a crackdown on underage clients.
The town hall asked undercover volunteers to try to top up their tans in recent weeks in the lead up to school prom season.
A dozen shops placed under scrutiny all refused the youngsters - an improvement on last year when staff at five of them did not ask for ID.
Other salons investigated as part of the same crackdown had introduced more robust checks on customers, the town hall said.
Council assistant director Mark Tilley said: "It is extremely important that sunbed salon owners are vigilant when allowing members of the public to use their sunbeds.
"We are pleased businesses refused our child volunteers on recent visits but want to remind operators of their legal responsibilities so they can help to protect our children and young people."
Since 2011 it has been a criminal offence to allow under 18s to use a sunbed. The town hall is urging borough salons to adopt a 'challenge 25' age check policy.
In addition to the legal ramifications of underage use, health bosses have highlighted the risks of regular sunbed sessions.
Prof Kate Ardern, the borough's director for public health, said: "Sunbeds give out ultraviolet (UV) rays that increase your risk of developing skin cancer later in life.
"The risks are greater for young people with evidence showing that people who are frequently exposed to UV rays before the age of 25 are at greater risk. While a tan can fade quickly, the long-term damage is irreversible.
"We would encourage young people to use safer alternatives such as tanning creams or spray tans."
