Isle of Wight Council Trading Standards Service is praising businesses in Ventnor and surrounding areas following a test purchase exercise.
In the build up to Bonfire Night, many shops are selling fireworks which have a legal sale age of 18.
Supervised by undercover Trading Standards officers, a 16 year old boy attempted to buy a packet of sparklers from four shops.
In each shop visited, he was asked for ID and was refused service.
Isle of Wight Council Cabinet member with responsibility for community safety Barry Abraham said "It is very encouraging to see businesses being proactive and checking the age of consumers who try and buy age restricted products.
"Fireworks can cause damage and serious injury if they are misused and this is one reason you have to be 18 to buy them.
"While we are happy with the results of this exercise in Ventnor, Trading Standards officers, with the support of the police, will continue to carry out test purchase exercises across the Island for a variety of items"
Age restricted items includes alcohol, fireworks, knives, cigarettes and certain types of aerosoles. Shops that sell items to underage customers could be liable for large fines, and in some cases could even lose their trading license.