Thousands of students are expected to gather on Ezra Avenue at Waterloo on Sunday for another unspecified party on St. Patrick's Day.
Regional police Waterloo and Wilfried Laurier University remind people of being "smart, safe and respectable".
The police will have a significant presence in the area and implement driving programs during the weekend.
In a press release Sunday morning, the police said some parties and gatherings had already begun.
"Today, our priority is public security, mass control, and law enforcement", Konst. Ashley Dietrich said.
"Our officers are here and apply the roads, as well as laws. They are ready to issue all the cards to anyone who is in violation of the law."
While the police do not approve of illegal gatherings, drinks or drug use, Dietrich says that people who choose to consume drugs or alcohol are encouraged to do so safely.
Kevin Petendra, deputy head of the Waterloo Paramedics Service, said anyone present at the party was encouraged to carry identification in the case of emergency medical help.
Maintaining the coverage of ambulances across the region will be a top priority throughout the day, he added.
"We have sorted out a significant number of additional resources to proactively address the negative impacts that this non-monetary set has on our services" Petendra said.
In tweets, university officials say: "Laurier actively refuses to sanction the streets." Students who violate any law or university policy may face sanctions under the code of conduct of the school.
Information on the police approach to St. Patrick's Day, penalties and university policy was published on Laurier's website.
Last year over 22,000 were attended by foreigners. The police raided 619 charges, and 52 people were hospitalized.