The creation of Plusnet Mobile is the result of joining forces with LIFE Mobile, part of the EE business, which was acquired by parent company BT this year.
Existing LIFE Mobile customers will become Plusnet Mobile customers from November 29.
Plusnet CEO Andy Baker said: “This is an incredibly exciting moment in our company’s history. True to our Yorkshire roots, Plusnet has always prided itself on offering customers more for less, and extending our offering to include a mobile service is a natural next step as we move to become a full-service quad-play provider.
“With the launch of Plusnet Mobile, we’ll be helping more people stay connected on-the-go with our fantastic data-packed deals and highly competitive rates.”
In October, Plusnet announced record profit after tax of £43.4m, up 35 per cent on the year previous, as the firm capitalised on the nation’s love for Yorkshire.
Turnover grew 18 per cent in the same period, while customer numbers were up 13 per cent, although the total is deemed too commercially sensitive to reveal.
Employee numbers grew eight per cent to 1,200, with 1,000 in Sheffield, based in the Balance office block on Trippet Lane, and 200 in Leeds.
Plusnet is Sheffield’s biggest tech firm.