Pub goers will have to give leave their name and contact details before they order a pint in England under new rules.
There will also be no live acts or standing at the bar allowed, the Government said in advice for re-opening the sector next month.
Pubs, restaurants and hairdressers will have to keep a record of customers for 21 days to assist the state health service's test and trace operation, which aims to identify and contain any local flare ups of Covid-19 and stop a second wave of infections.
British Prime Minister Boris Johnson said on Tuesday pubs, restaurants and hotels could reopen in England on July 4, easing the coronavirus lockdown that has all but shut the economy.
He also reduced social distancing from 2 metres to 1 metre, a change that will allow many more pubs and restaurants to reopen.
The British Beer & Pub Association (BBPA) said 75% of pubs in England - 28,000 in total - would be able to reopen. Under 2 metre social distancing rules, only a third of England's pubs - 12,500 - would have been able to reopen.
BBPA chief executive Emma McClarkin said: "As an industry we will be doing everything we can to ensure both our customers and staff are safe in our pubs.
"We do have significant concerns over the collection and storage of personal customer data when visiting the pub."
Her concerns were echoed by privacy experts.
Ray Walsh, digital privacy expert at ProPrivacy, said: "People's contact information is extremely sensitive, and it is important for strict measures to be put in place to ensure that data is handled in accordance with GDPR.
"The sad reality is that people's contact details could potentially be inappropriately handled by pub staff, opening consumers up to all kinds of privacy and security risks."
Walsh pointed to a case in New Zealand, which has similar rules in shared spaces, where a Subway employee harassed a woman via text after her details were stolen from a contact tracing form.
He added: "While preventing the spread of Covid-19 is important, the safety of consumers and their data must also be assured and the onus is now on the government to provide strict guidelines over how that data collection will be enforced in such a way that makes it safe for the general public and their data."
Business Minister Alok Sharma said he would consult with the industry on data regulation, noting that restaurants and hairdressers already kept information when people made bookings.
"We what to work with the sector, we want to work with trade unions, to make sure we get this absolutely right and I'll be doing that later on this week," he told LBC radio on Wednesday.
