Three, which is owned by Hutchison, said it would start its 5G network with a London home broadband service, joining BT's EE and Vodafone in launching services in 2019.
Three said its 2 billion pound 5G infrastructure investment included network improvements in major British cities and a cloud core network provided by Nokia.
"It's clear that consumers and businesses want more and more data," chief executive Dave Dyson said in a statement.
"We have worked hard over a long period of time to be able to offer the best end-to-end 5G experience. 5G is a game changer for Three."
EE launched 5G services in six cities in May, while Vodafone will launch on July 3. Both pulled Huawei smartphones from their 5G launches because of uncertainty about support by Google's Android after a U.S. move to block the Chinese firm's access to its technology.
Three said that they would announce details of which handsets would be part of its mobile launch in July.
The United States has said Huawei is a security risk and open to spying by Beijing, a claim the Chinese company denies.
Britain's National Security Council decided in April to block Huawei from all core parts of its future 5G network but to give it restricted access to non-core parts, but the government has not made a final decision.
The worldwide commercial launch of 5G is expected in 2020. - Reuters
We're sorry, this article is unavailable at the moment. If you wish to read this article, kindly contact our Customer Service team at 1-300-88-7827. Thank you for your patience - we're bringing you a new and improved experience soon!