Retailers in Llandudno have been tested on their compliance with the law and sale to young people and children.
Further test-purchasing operations were overseen by officers in Llandudno this week.
The sale of vapes was in focus on this occasion, following a similar operation that targeted knife sales last month.
A total of 11 shops were visited across the town, of which 10 were found to be in compliance with the law.
However, one retailer illegally sold a vape to a 14-year-old customer.
All stores will be revisited in the weeks ahead for further checks.
Sgt Paul Cassidy said: "We will continue this proactive work across the area to ensure that all retailers are meeting their legal responsibilities when selling age-restricted products.
"Protecting young people is a foremost priority, and we will not hesitate to take further action where businesses fail to comply with the law."