Cardiff becomes one of the first cities in the UK to get 5G connectivity
5G technology is the next generation of mobile network and is expected to offer internet speeds several times that of current generation 4G.
Operator EE is launching in five other cities: London, Cardiff, Belfast, Edinburgh, Birmingham and Manchester - with more to follow before the end of the year and into 2020.
Fellow mobile operator Vodafone has confirmed it will launch 5G across seven cities in the UK on July 3, with another 12 cities to follow by the end of the year.
A number of 5G-capable handsets are available from Samsung, OnePlus, LG, HTC and Oppo, but Huawei has been left off amid ongoing tensions between the US and the Chinese company.
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Critics say more needs to be done to boost connectivity in other parts of Wales first.
In January a National Assembly Committee said mobile phone coverage in Wales already lags behind the rest of the UK.
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Find out more about 5G here.