The car boot sale at Ashton Common in Trowbridge was one of the first to reopen this morning at 5.30am.
Organisers urged visitors to obey the coronavirus regulations they have put in place.
A spokesman said: "We have put Covid-safe measures in place. Please look at the signs and obey the Covid rules."
The organisers have improved the entrance to the site on the Ashton Road just off the A350 to make it easier for vehicles to enter and leave.
The Ashton Common Car Boot Sale has been running since 2004. It aims to be a family friendly community boot sale that gives back.
Since opening it has raised over £80,000 for Cancer Research UK and has been recognised by the charity for its fundraising efforts.
The Innox Mills Sunday market in Trowbridge is also back today from 9am to 3pm offering a mix of artisan products, street food, local produce and vintage clothing.
Jonathan Dean, director of Innox Mills, said: “In 2020, the market regularly drew around 3,000 visitors from the town and further afield, and we’re expecting these new dates to prove just as popular.
“Following the success of the Christmas market, where we made use of the buildings which provided a great rustic backdrop, we felt they would also provide an ideal setting for the regular market, which will include a street food courtyard with a seating area when restrictions are permanently lifted.”
Organised by the Innox Mills site owners in partnership with The Anonymous Travelling Market, the event is being held in the historic buildings at Innox Mills, where visitors will be entertained by live music while they browse the stalls.
This includes the Grade 2-listed Innox Mills building, the former dye house, brewery and cloth factory along the riverside, which date back to the 19th Century.
Social distancing measures will be in place to protect visitors and stallholders, including a one-way system.