Mike Sievert
Chief Executive Officer at T-Mobile US
Thanks, Cathy. Hi, everybody. Welcome to the call. We're coming to you from New York today and if you're watching online, you can see I'm with several members of the senior team, ready to discuss these strong quarterly results and our recent news and of course to take your questions. This T-Mobile team just continues to demonstrate strong execution across the board and we're taking up our customer growth and cash flow guidance for the full-year once again.
I'm going to begin with a comment on customer growth, because this quarter not only represented our highest ever Q2 postpaid phone net adds in company history, but we also pushed past a major milestone, 100 million customer connections. This growth was once again balanced geographically across both smaller markets and rural areas and top 100 markets. We also grew our postpaid phone gross adds at the highest rate in nearly three years. And at the same time, we delivered yet another record low upgrade rate this quarter, speaking to the strength of our customers experience on our differentiated 5G network.
And speaking of experience, let me now turn to that network leadership. We swept every category for overall network performance in the latest open signal and Ookla tests. According to Opensignal, T-Mobile's download speeds are up to three times as fast as peers, alongside having nearly six times the 5G availability as our next closest competitor. And our network was also awarded the most consistent by both independent third parties, a key indicator of an overall superior network experience.
We continue to invest thoughtfully and in a highly capital efficient model to extend our network leadership and it shows. It is really a privilege to see our team's hard work show up in recognition like this and to share it with you. Okay, turning to broadband, our fixed wireless offering continues to resonate with customers, leading us to capture a record share of industry broadband net adds this quarter. And now we have an incredible 5.6 million fixed wireless broadband customers.
I hope you all saw our news from last week, as I'm excited to talk to you about our partnership with KKR to acquire Metronet. The Metronet team is the nation's fastest growing pure play fiber provider. This is a unique company and asset. They already reach over 2 million homes today and with this partnership are expected to grow to 6.5 million homes passed by 2030, bringing consumers greater choice where they need it most. And we are equally excited to work alongside KKR's expert infrastructure team on this project. And as with our Lumos JV, T-Mobile will leverage our scale, brand, distribution and existing customer relationships to grow faster and to do it smarter.
I can't highlight enough how both the Metronet and Lumos JVs represent best-in-class partnerships in the fiber space because of the partners that we've chosen and T-Mobile's unique assets and capabilities, I believe this is going to be a very successful initiative for our shareholders.
Now going back to the current business and our financials. In Q2, we once again demonstrated our ability to deliver profitable growth in customers and translating that to industry leading service revenue growth and industry leading core adjusted EBITDA growth. That combined with our capital efficiency has led to a record adjusted free cash flow quarter that grew 54% year-over-year and once again led the major wireless companies in free cash flow margin. I could not be more proud of this team's results this quarter.
Okay. To sum it all up, we are staying true to our Un-carrier DNA while focusing on smart and profitable growth delivering record financial results. Our durable and differentiated model continues to outperform and I look forward to sharing more about the Un-carriers next chapter on value creation at our Capital Markets Day, which will be in the second half of September and we're going to get that on your calendars very soon.
So Peter, let's hand it to you to talk about our key financial highlights and an update on our guidance.