Published last Thursday (11 August), the results showed 9,532 alcohol breath tests and 199 roadside tests for drugs were administered, with more than 430 returned positive.
Of the tests for alcohol, 306 returned positive, refused or fail to provide (3.2%), while 131 showed positive for drugs (65.8%).
Led by Dyfed Powys Police, the campaign ran between 10 June and 10 July, coinciding with this summer’s European Championship in which Wales reached the semi-finals.
In comparison to recent years, fewer alcohol breath tests were made but there was an increase in the percentage of tests failed.
During the 2015 campaign police officers carried out 12,920 breath tests, 353 of which tested positive (2.73%) while in 2014, a total of 15,485 breath tests were administered, of which 358 (2.3%) were over the limit.
52 arrests were also made in 2015 under the then new drug drive laws.
Assistant chief constable Pam Kelly of Dyfed Powys Police, who led the campaign, said: "This campaign identified a significant number of motorists in Wales who continue to ignore this important legislation around drink and drug driving.
"Although this was a month-long focussed campaign, the drive to change attitudes, increase road safety and catch offenders will continue year round.”
Susan Storch, chair of Road Safety Wales, said: “We were clear in our messages throughout the campaign that drink or drug driving is not acceptable, and will not be tolerated.
"Those that selfishly break the law are endangering themselves and, more importantly, other road users. Drink and drug driving ruins lives all year round and we will continue to work closely with the police in reinforcing these messages throughout the year."