About 2.5 million people in the UK are behind on broadband payments, according to a survey from Citizens Advice.
The number has jumped by about 700,000 since before the pandemic, when 1.8 million people owed money to their provider.
Young people and those with children under 18 were worst affected.
Households receiving universal credit were nine times more likely to be behind on their broadband bills than those who were not.
The Citizens Advice survey conducted in March 2021 involved 6,001 people.
In December, UK telecoms regulator Ofcom urged providers to offer cut-price deals to those currently on universal credit.
Currently, Virgin Media and BT are among the few UK providers offering such a discount.
Ofcom is expected to release a report this month looking at whether further action is needed.
“Lack of broadband creates yet another hurdle in the hunt for jobs, helping children with their schoolwork, and being able to access help, information and fill in forms online,” said Dame Clare Moriarty, chief executive of Citizens Advice.
“People shouldn’t be penalised simply because their provider isn’t one of the few firms that offers a cheaper tariff.”