The centre, at Askham Bar outside of the city centre, has vaccinated over 300,000 people since it opened in January.
It is now welcoming anyone over the age of 18 for their first vaccine dose regardless of whether they have an appointment booked.
People who had their first dose over eight weeks ago are also encouraged to walk in for their second vaccination at the centre, which is run by Nimbuscare.
Staff at the centre said they have vaccinated more than 2,500 people since walk-in appointments were introduced, including at pop-up centres across York Prof Mike Holmes, chair of Nimbuscare and clinical lead of York NHS Vaccination Centre said: “This was a Nimbuscare decision in conjunction with the public health team in York – it was a risk, but was the right thing to do. It was about lowering the barriers for people to access the vaccination centre.
“We’ve already vaccinated more than 320,000 people, but there are still more who, for whatever reason, haven’t been yet.
“Opening the site up to walk-ins means people who can’t access a computer or phone, or people with no NHS number or those not registered at a GP practice, can still get their jab.
“It also gives people flexibility and convenience as we’re open 8am til 8pm seven days a week.
“It’s likely we will continue working like this for some months, as long as it is effective at getting more people protected.”