The  review, for Welsh ministers, estimates between £17m and £22m raised by the 5p charge has been donated to good causes by retailers.
Natural Resources Minister Carl Sargeant said the levy had produced a significant shift in consumer habits.
Carrier bag charges begin in England next month, for large retailers only.
The report said 74% of shoppers backed the charge and found the use of "bags for life" and other re-useable bags had resulted in an overall reduction in all bags of 57%.
Mr Sargeant said: "We wanted the people of Wales to get into the habit of reusing their bags when shopping.
"I am pleased that almost four years on from the introduction of the charge in Wales consumer habits appear to be changing which is having a positive knock on effect on the environment as well as raising a significant amount of money for good causes."
Wales was the first UK nation to introduce the bag charges, followed by Northern Ireland and then Scotland.
The number of single-use carrier bags handed out by shops in Wales has fallen by 71% since charges were introduced in 2011, according to a report.