The move towards digital has led Virgin Media to cut almost 800 jobs in Swansea.
The decision is part of a £40 million plan to create “fewer, higher-quality workplaces” as Virgin Media reduces its number of customer operations centres from eight to four.
Call centres in Swansea and Nottingham are to close in the next two years. A total of 792 staff are employed at the Wales base, 552 in permanent roles and the rest as subcontractors.
The telecoms giant, which employs 14,000 people across more than 100 sites, said 470 of the permanent roles are being switched to Wythenshawe in Greater Manchester.
“We have proposed the closure of a small number of our offices over the next two years, including our call centre in Swansea and our current site in Nottingham,” said chief executive Tom Mockridge.
“These changes will help deliver a more agile, digitally oriented experience, which our customers increasingly expect as standard.”
He added: “We are now working with and supporting all employees who have been asked to relocate, who may be in a role at risk of redundancy or who may wish to take another role with Virgin Media or one of our partners.”
The Welsh government also said it would support affected staff.
Swansea West MP Geraint Davies described it as a “catastrophe for our city”.
“I’m stunned by the Virgin job losses, which is a traumatic shock for every family concerned and a body blow for Swansea,” he said.