Non-essential shops in England and Wales, as well as gyms, theme parks and hairdressers, were allowed to welcome customers again, more than three months after being forced to shut.
Several bosses told us all they had done to prepare for the big reopening - from paint jobs to buying new furniture.
They told BBC News how the first week of trading in the "new normal" went.
Afolabi Akinola, Emeka Obanye and Joshua Oladimeji, founders of Elite Evolution, in Hackney, London, have made big changes in the time their gym has been closed.
They've upgraded the booking system, sanitised equipment and introduced new rules on not sharing boxing gloves.
Since reopening, they have allowed six clients in to train at a time, each working out within their own taped-out area.
"Reopening feels like we re-launched again - just like the good old days when we first started. We were really nervous but people seem revitalised," says Joshua.
The gym has seen about a 30% uplift in enquiries for personal training sessions and bookings for training slots since Monday.
"Our business line is buzzing with people wanting to come back," he adds.
In order to keep up with demand and ensure people can train at quieter times, they've been open 24 hours a day. Joshua says one client has booked in at 05:00 every day, while others have organised evening workouts around fasting periods during Ramadan.
He adds that the first week back has had a real "feel-good factor", with customers telling them getting back in the gym has boosted their mental health.
It's a lesson the firm is keen to take forward: "Covid and lockdown have brought about sadness, people losing loved ones and other challenges.
"We're trying to be more than just a gym and really put our focus on that mental health aspect too... although we do need specialist help and know it's a big challenge."
"'It's just been chaotic, but so lovely. It's so nice to see staff and clients back," says Stacey Manning.
In her hair and beauty salon, Ooh La La, in Coventry, customers have been booking up slots for total transformations.
"We're getting phone calls on the day with customers asking if we can squeeze them in - coming in with brown hair and asking to go bleach blonde!"
In the first week of trading, her team of hairdressers have largely been working from 08:00 until 20:00, while "quite a few" new clients have started plans for Botox treatments.
"These treatments aren't just cosmetic," Stacey adds. "People are leaving so happy after having a transformation after a year of staring at themselves on a computer screen and picking apart their flaws."
And the diary doesn't look set to quieten down until the end of May, although the salon is working at about half capacity to ensure social distancing.
Stacey has also been heartened by the return of some elderly clients. "One of our ladies has had both vaccines and sat there full of confidence having gels put back on her nails... in the previous lockdown you could hear how nervous she was in her voice.
"It's so nice seeing people more relaxed as restrictions ease - everyone seems so happy and excited."
On Monday morning, Julie Dalton, manager of Gulliver's Valley theme park in Rotherham, Yorkshire, walked across the car park performing final checks before thrill-seekers were allowed in.
"Hearing the music was a huge relief," she says. "It meant we were opening up again."
"We've not made a money since before Christmas and that's a long time not to have money coming into a business," she adds.
The park will reopen each weekend, with all of the available pre-booked slots taken.
Julie believes that a change of scene is what customers are after, following months of lockdown restrictions: "It's something different and means the kids have a bit of normality.
"A bit of blue sky and sunshine is what we desperately need as a nation - and people just need to be out and about for their mental health."
While she describes watching customers and staff return as a weight lifting, reopening has brought some challenges.
The theme park - which offers rides, attractions and mini-breaks - can't run shows, its restaurants are closed for indoor dining, and staff and customers must socially distance.
Like last summer, some guests have pushed back on the requirement to wear face masks on rides.
Julie says: "You have to deal with that, point out the markers and explain the face masks are there for a reason. I have to protect my team and you have get up close to people when you're checking seat belts or lap bars."
But she adds: "It's been incredibly positive overall - just knowing that the smiley faces are there behind the masks."
At Nostimo restaurant in central London, Monday saw a slower start to the day.
That was until the lunchtime service. "After 12:00, it exploded. We were full the whole time, with the next customers outside waiting and we were going like crazy", says Michael Petsalakis.
He says each day has been "extremely busy", with income increasing by 270% in comparison with when the Greek restaurant was just offering delivery services.
All in all, the firm spent £130,000 on improvements ahead of reopening, which included taking over the space of a Mexican restaurant which closed next door.
Its outdoor dining areas, with brand new furniture and recently laid wooden flooring, are fully booked until Wednesday, with the exception of a few spaces for walk-ins.
Michael says customers have been like "children getting to go outside for playtime", favouring traditional Greek dishes such as moussaka or souvlaki.
He adds it's been a "pleasure" to see the return of the four members of staff who spent 12 months on furlough.
"We have missed seeing our staff and our customers' faces - that's why we're in the hospitality business."