Fines were handed out after police broke up a party of 14 rugby fans watching Wales lose to France.
It was just one of the offences officers were called out to as South Wales Police dealt with nearly 1,500 incidents on Saturday.
Superintendent Marc Attwell described it as "one of the busiest days of 2021 so far" for officers in the force area.
At least 32 fines were issued in Merthyr Tydfil where police found 14 fans watching the thrilling Six Nations game on a projector, where Wales were cruelly denied a Grand Slam in the final minutes of the game.
In Swansea, officers said they were also called out to reports of parties organised for the rugby match and for the South Wales derby between Cardiff City and Swansea.
Officers said on social media: "It's been a busy one tonight [Saturday] with the football and rugby. PCSO officer has been all over Eastside attending at reported parties, conducting welfare checks and carrying out hotspots patrols.
"Please adhere to the guidelines, stay safe out there."
Households are not allowed to mix indoors due to current coronavirus rules, while First Minister Mark Drakeford, police and doctors had urged fans to watch it in their own homes and not mix.
Mr Drakeford had urged on Friday: "If you’re watching Wales this weekend, please watch with members of your household only.
“The last thing we want is to mark a potential Grand Slam weekend with a surge in Covid cases.”
