The cost of a single-use plastic carrier bag in English shops has gone up from 5p to 10p.
All stores, big and small, have to apply the charge from Friday. Until now, smaller retailers were exempt.
The original 5p levy was introduced in England in 2015. Since then, the use of the bags has declined by more than 95%.
Campaign group Friends of the Earth urged the government to go even further, saying the bags were part of a bigger plastic problem.
The group welcomed the scheme, but said it still had "significant shortcomings".
Campaigners said the charge should be extended to paper carrier bags, while so-called "bags for life", which are designed to be reused but contain greater amounts of plastic, were posing a "growing problem".
"It seems that many plastic 'bags for life' are being used just once and not reused for the bag's lifetime, as is their purpose," said the group's plastics campaigner, Camilla Zerr.
"If ministers want to get to the root of this problem, they need to take a tougher stand against all single-use plastics."
The environmental group's warning has already been heeded by supermarkets including Morrisons and the Co-op, which have discontinued the sale of plastic bags for life.
Friends of the Earth said the government's forthcoming Environment Bill should include "legally binding targets" to phase out the use of all unnecessary single-use plastic products.
The average person in England now buys just four single-use carrier bags a year from the main supermarkets, compared with 140 in 2014.
By extending the charge to all retailers, the government hopes the use of single-use carrier bags will fall by 70-80% in small and medium-sized businesses.
Environment minister Rebecca Pow said: "Everyone wants to play their part in reducing the scourge of plastic waste that blights our environment and oceans.
"The 5p bag charge has been hugely successful, but we can go further."
She added that the new higher charge in England would "support the ambitious action" the UK has already taken in its fight against plastic, "as we build back greener".