Revellers will receive £75 fines if they are caught urinating in streets and doorways instead of using open-air urinals in Swansea city centre.
The council started to provide portable urinals two years ago following complaints by local businesses.
The move was welcomed by many traders in Wind Street, which is popular with drinkers, but the problem has not gone away.
From Friday, police will start handing out fixed penalty notices.
"Urinating in public is a major irritation to authorities and businesses who are left to clean up their own doorways and streets after people under the influence of alcohol feel it is acceptable to treat the city centre like a toilet," Ch Insp Dean Thomas said.
"It is certainly not acceptable and I am pleased the police are able to work with the council in enforcing fixed penalty notices against those caught in the act."
The pilot operation between the council and police is aimed at ensuring the public knows urinating in the street will not be tolerated.
The council deploys portable urinals every weekend in the city centre at known problem areas and says they are well used.
'Control their bladders'
But not everyone chooses to use them, prompting the latest move follow a warning two years ago that anyone caught would be fined or arrested.
Bruno Nunes, owner of Peppermint bar and Bambu Beach bar, welcomed the action.
"The impact of this action will be felt not only by those hit in the pocket, but the many others who will hear about the tough stance being taken," he said.
Council cabinet member June Burtonshaw said: "Public urination is a contentious issue that has been troubling authorities, organisations and businesses working together to create a cleaner, healthier and safer city centre.
"We've tried the soft approach, which has had some effect, but now it is time to get tough. Urinating in shop doorways, alleys, lanes or bushes is not acceptable.
"There are toilets provided in every night-time venue, as well as the additional portable urinals on the streets. If people still can't control their bladders, they could find themselves with a hefty fine."
Similar toilets are used in other UK cities including Manchester, Bristol, Cambridge and London.
Wind Street has come under fire in recent months being dubbed "an area of drunkenness and debauchery" and a "magnetic attraction" for drinkers.
In response, the council has introduced a policy curbing new pub and club licences in the city centre.