The service will launch in London, Edinburgh, Cardiff, Belfast, Leeds, and Slough first in November, with 20 in total added before the year is out.
And by the end of 2020, they aim to take the number up to 50.
At the moment, 5G is only available on the Huawei Mate 20 X 5G handset, with the Samsung Galaxy S10 5G to follow.
The news from Sky comes after Three announced their rollout of 5G broadband in London this August.
The mobile operator revealed their plans to launch the service to the British capital, and to bring 5G mobile and home broadband to 25 towns and cities before the end of 2019.
The Hutchison-owned firm's Chief Executive, Dave Dyson, said: "It's clear that consumers and businesses want more and more data.
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."
Three follow in the footsteps of EE, who overtook Vodafone with the announcement of their 5G service being rolled out in six cities in the UK last month.
The mobile network - which is a division of BT - brought the first phase of their high-powered service to London, Cardiff, Edinburgh, Manchester, Birmingham and Belfast on May 30, four days ahead of their rival.
The first phase will last until 2022, when the newest technology will be available. Whilst the third phase will launch in 2023.