Coronavirus rules are now relaxed, along with hair and nail salons, outdoor bars and restaurants for table service, libraries and gyms.
Face masks could still be required for shops until June 21, which marks the earliest point at which the country could return fully to normal living.
Tracey Flear, who has run Baskets & Bunches florist in the town centre for more than 30 years, said: "It's been a bit strange, but I am so glad to be back open.
"I really enjoy my work and I've been very bored at home."
Police Community Support Officers Mia Ball and Charlotte Jones have been keeping shoppers and business owners coronavirus safe.
Mia said: "It's nice to see some life in the town centre again."
"It's buzzing," added Charlotte.
Shopper Di Sheppard, who lives in Daventry, said more people should visit the town, which also has a Waitrose, Boots and New Look.
"There's a good array of shops in Daventry," she said.
"It's a lovely clean town and my favourite shop is Prezzance. I always find the perfect gift in the shop and the owner is so helpful."
Visitors made the most of the sunshine and took advantage of the many coffee shops and places to eat.
Ricky Singh, owner of KITCHEN, said: "We have worked all through lockdown and our customers have been very loyal to us.
"It's great to be open again we look forward to welcoming our customers back - old and new."
Lorna White, co-ordinator of the Daventry Retail Forum, said: “We are thrilled Daventry is open for business again and the weather couldn't be better.
"It's so nice to see the town alive again. Daventry is a great town with more than 100 independent shops and free parking all year round."
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Tracey Flear, who has run Baskets & Bunches florist in the town centre for more than 30 years, said: "It's been a bit strange, but I am so glad to be back open.
