Large amounts of rubbish have been left strewn across Cardiff Bay on Sunday morning.
Pictures online showed large groups of people gathered at the Roald Dahl Plass on Saturday.
The aftermath the following day showed bottles, rubbish, carrier bags and overflowing across the bay.
There have been a number of gatherings in the area during lockdown. It comes after the 5-mile travel rule was lifted in Wales.
On Saturday, beaches and beauty spots across Wales saw an influx of people.
Porthcawl beach and Barry Island were busy, while visitors to Snowdonia were left to park their cars on the sides of roads after car parks were full.
Cardiff Bay has become a litter hotspot during lockdown as large groups of people gather to drink and socialise in the area.
Last month, the area was once again littered with empty beer bottles, cans and canisters of the drug Nitros Oxide (more commonly known as laughing gas).
The following morning council workers were seen out cleaning up piles of rubbish.