A wedding with a "large number of people" was shut down by police on Thursday - with everyone there forced to leave.
South Wales Police was called to Adelina’s Bar and Kitchen on Mumbles Road on Thursday following a report of a large gathering that breached coronavirus regulations.
Officers found a "large number of people" upon arrival and understood the event to have been a wedding reception.
And it came just a day before the Welsh Government announced Swansea would be going into local lockdown.
All guests were forced to leave and officers issued the owners of the restaurant with an immediate closure notice, Wales Online reports.
The restaurant in Swansea now has 14 days to put in place a series of measures to enable two-metre social distancing and implement controlled use of toilet facilities.
Owners are also expected to make sure the layout of the premises can accommodate customers.
It came on the eve before the Welsh Government announced Swansea would be going into local lockdown.
Councillor David Hopkins, cabinet member for Delivery and Operations said: “We told businesses that we would take firm action if they failed to comply with Welsh Government rules.
"The latest lockdown measures mean it is now more important than ever that businesses pay attention to the latest regulations so we can keep the public safe and help prevent the spread of the virus.
"Many businesses in the city are doing the right thing, taking their responsibilities seriously and abiding by the rules.
A spokeswoman for South Wales Police said: "South Wales Police responded to a report of a gathering at the Adelina’s Bar and Kitchen, Mumbles Road, Swansea, at approximately 7.10pm on Thursday, September 24.
"Upon arrival officers found large number of people in attendance at a private function.
"The function was shut down and all attendees ordered to leave.
"Further enforcement action by South Wales Police and Swansea Council is currently being considered."