The British company paid £8.7m (121m kronor) to acquire the Swedish operator's customers.
Tele2 entered the British market in 2003 and the Irish market in September 2004, offering fixed telephony services.
In a statement Tele2 said that it decided to quit the two markets after it realised that plans to offer broadband services in the UK would not be profitable.
While the sale of the fixed line business to Carphone Warehouse will mean the phasing out of Tele2's brand in the UK, the company will still have British operations in the form of Alpha Telecom, 3C and C3.
“The decision to divest our UK and Ireland operations has not been taken lightly and is a result of thorough analysis of the market and our various options,” said Lars-Johan Jarnheimer, CEO and president of Tele2.
“We can get significantly better returns by reallocating its budget to other markets,” he added.