Officers were called to a group of around 20 people congregating on the Clevedon seafront.
Avon and Somerset Police said in a statement it was called to a number of people congregating near Marine Lake in Clevedon on the afternoon of Tuesday, April 7.
The force said: "The group was leaving the scene when officers arrived.
"But before they left officers explained the current rules and provided advice to them around social distancing and essential travel."
They confirmed reports received estimated 10-20 people were there.
An eyewitness said: "I think it’s disgusting - we are all trying to stay safe and look after our loved ones and the NHS.
"None of us likes being stuck in all the time but, if we want to come out of this as soon as possible, we need to stick by the rules.
"I have not seen my mum now for three weeks and then you have people like this - not just going out, but going out to picnic and party.
"It’s a joke."
Another eyewitness said he saw the gathering as he went out on his bike ride at around 2pm, adding it was a group of around 20 people of all ages.
"I didn't really like it to see people just ignoring the advice - it is not good," he added.
