Anyone 18 or above will be able to turn up to "grab a jab" at one of the sites, which the NHS will publicise locally.
The health service will also this weekend send mobile vaccination sites out on the road and plans to visit housebound people as part of a drive to increase uptake.
A new online service enabling people to find their nearest walk-in site simply by entering their postcode is being set up and text messages will be sent to nearby residents who have not had their first dose.
Those who attend a walk-in clinic for their first dose will have their vaccination record updated online and will then be able to book an appointment for their second dose using the national booking system.
Dr Emily Lawson, NHS England's lead for the vaccination programme, said: "If you haven’t yet got vaccinated for whatever reason, this is the weekend to get that sorted and join the tens of millions who have protected themselves and their loved ones from the virus."
Second doses will also be available at the walk-in sites and the NHS stresses that getting both jabs is vital to achieving full protection from the virus.
Dr Lawson said: "Please bring forward your second jab if it’s eight weeks or more since your first, when contacted to do so by the NHS, so that you get the maximum protection offered by the vaccines.”
Every adult in the country became eligible for a jab last weekend and more than one-third of the youngest group (aged 18-24) have already been vaccinated.
More than 63 million jabs have been given in England since the vaccination programme began in December, with more than 80 per cent of adults having received their first dose.
The NHS aims to have vaccinated all adults by 19 July and said it is delivering jabs as they become available in the run-up to the target date.
Sir Simon Stevens, NHS chief executive, said: “With more than 63 million jabs already delivered by the NHS in England, we're now in a race to the finish line ... So this weekend why not join millions of others and 'GrabAJab' to take advantage of this life-saving protection.”
Nadhim Zahawi, the vaccines minister, said vaccines were the "way out of this pandemic" and urged those who could to visit a walk-in centre this weekend.
He said: “No matter where you live, where you come from, your background or your beliefs – provided you are over 18, there is a vaccine available to you."