Mike Sievert
President & Chief Executive Officer at T-Mobile US
...will continue to keep us ahead in this race over the next years with our great spectrum assets in both depth and breadth deployed rapidly and our rapid execution of our unique process called customer-driven coverage, and finally, continued leadership and implementing advanced technologies such as standalone 5G and multi-carrier aggregation. All of these things, importantly, are contributing to the best capital efficiency in our sector.
All of these strengths, coupled with our unique opportunity in underpenetrated markets, are what enables a differentiated and profitable growth strategy that separates us from the competition. And you know what, we showed that again in Q1. We added 287,000 postpaid account net additions, the highest reported in the industry once again. And that means we're winning the switching decisions in the market, because this looks at it at the account level. And we had postpaid net additions of 1.3 million more than AT&T and Verizon combined. This included postpaid phone net adds of 538,000. We won a higher share of net adds year-over-year, even as the industry continues to moderate just like we predicted we would in previous calls. Our increased share was driven by our strong phone gross adds, as well as being the only national wireless provider to improve postpaid phone churn year-over-year.
Our consistent approach to profitable growth continues to deliver right on and sometimes even above our ambitious plans. And that's even as the competitive landscape continues to shift and evolve. In recent quarters, we've seen cable giving away free first lines that don't, by the way, appear to be incrementally pulling from existing customers and incumbent providers, but definitely are driving their ARPUs down.
We've seen AT&T and Verizon significantly outspend us in media advertising. I mean, Verizon alone has spent almost 60% more than T-Mobile in Q1. And we continue to see, as I mentioned earlier, others lean into expensive long-term device contract offers to lock-up their customers, while T-Mobile was the only one to improve churn year-over-year and have the lowest upgrade rate. Improving churn, but with the lowest upgrades. That's because our approach is not to slam customers with expensive unwanted upgrade contracts to tie them down for three years. Customers genuinely choose to stay with T-Mobile for the network, for the value proposition, and for the experiences. And you know what, that's how we want it to be.
You've heard us say before, our strategy is differentiated and durable because it's driven by taking share in the places where we continue to be under-penetrated relative to the market, but where we now have new permission to win. This profitable growth playbook and the momentum we saw in Q1 is exactly what gives us the confidence to raise our postpaid net add and financial guidance for the year.
Perfect example of this, T-Mobile for Business, where we just posted one of our highest ever phone net add quarters in Q1 with the lowest business phone churn in our history. And we're profitably taking share with more business account net adds and more business phone net adds than Verizon in the quarter.
On the consumer side, we're winning with prime network seekers in the top 100 markets, who increasingly recognize that T-Mobile offers the best combination of network coverage and capacity for their needs. In fact, our prime customer base hit an all-time high again this quarter. And in smaller markets and rural areas, we are now capturing a win share of switchers in the upper 30s and that's in the roughly two-thirds of this geography, where we're competing. This is great news, because it's showing that our strategy here is very much on track.
In addition, we added 523,000 High Speed Internet customers as we have continued to grow our gross adds every quarter since we launched two years ago. I would expect that we added more broadband customers than AT&T, Verizon, Comcast and Charter combined for the fourth consecutive quarter.
And not only did we have the highest net adds, but our focus on profitable growth translated into strong financial performance with core adjusted EBITDA up 9% year-over-year, and free cash flow up over 45%. Our Q1 results were just the latest example of how we have lots of room to run at T-Mobile. And I'm confident in our ambitions for this year and beyond.
One thing you've come to expect from this management team is that we are never satisfied. And you saw that again with our latest Un-carrier move to free customers from three-year contracts and introduce New Go5G plans that offer even more value than before.
As proud as I am of what we've accomplished in our 10 years as the Un-carrier and in Q1 most recently, I am even more excited about what's ahead for T-Mobile. And I'm so thankful that all of you are on this journey with us.
Okay, Peter, over to you to talk about the key financial highlights and our updated guidance for '23.