The politician - who is the top Democrat on the US Senate Committee on Commerce, Science and Transportation - has called on the government to ensure the new development is dealt with the right way.
Speaking at a 5G hearing on Wednesday (06.02.19), she said: "I'm all in for 5G ... But in the push for 5G, we need to make sure we're not blind to some of the very important policy issues.
"5G networks must be secure, and that starts with having a 5G strategy that focuses on shoring up our defense against hackers and state-sponsored actors."
Cantwell urged the Trump administration to provide Congress with a "real, quantifiable 5G security threat assessment."
She also added that the US would need to make sure that equipment made and used for 5G networks - which promises increased internet speed, responsiveness and coverage - is secure.
She added: "If we roll up our sleeves, get serious about the cyber issues, and continue to make the right investments in the innovation economy and the race to win in 5G, the United States will do very, very well"