People in Yorkshire and Lincolnshire's coastal communities say an influx of visitors would be a "nightmare" after a change in travel restrictions.
The new rules, which come into force on Wednesday, say day trips to outdoor open spaces are permitted, and do not limit the distance people can travel.
Those living in seaside towns fear the change could put their health at risk.
Most facilities, from public toilets to cafes, along the almost 100-mile (160km) coastline remain closed.
Many of those who live along the coast are older - a group considered more vulnerable to serious complications if they are infected with coronavirus.
The over-60s represent about a third of the population in most of these seaside towns, according to the 2011 census.
Celia Barnes, a pensioner from Skegness, Lincolnshire, said she had been shielding for nine weeks and had not left her home.
She said: "I haven't even seen my grandchildren who live in Skegness. Now the beach is going to be open. How is this fair that we will be inundated with people flocking to the beach who might have the virus?"
Scarborough council deputy leader Liz Colling added: "We are already feeling quite vulnerable and we have worked hard to keep our infection rate low and we would like to keep it that way."
"Keep the visitors away and keep us safe," was the message from Ashley Collins from Ingoldmells; while Carl Teacher in Mablethorpe said the prospect of people coming was a "nightmare".
"They do not know whether they have the virus or not and it creates huge anxiety for residents," he said,
There are also questions about what visitors will do when they arrive.
"People have to remember that there are no public toilets open; there are no cafes open; the car parks are not open," Liz Colling said.
Scarborough resident Emma Zochling said: "That will end in everyone down on the beach, overcrowding, forcing everyone to break the social distance rule, then everyone will start parking on residential streets.
"People who live here will have to avoid going out where they live as it will no longer be safe to do so."
Shelagh Finley, a town councillor in Bridlington, tweeted her worries that people coming to the East Yorkshire town would not realise things were shut.
"But most of all I worry that travel will spread the virus to our town," she said.