Source: T-Mobile.

When John Legere became CEO of T-Mobile (TMUS 0.92%) back in 2012, one his main focuses was to build a strong LTE network that rivaled those of Verizon (VZ 0.90%) and AT&T (T 1.10%). It was a lofty goal, and he didn't waste any time trying to achieve it.

About a year after he took over, Legere said on an earnings call, "We've rapidly expanded our 4G LTE network in 2013. We went from, literally, 0 to 209 million people covered in just over 3 quarters."

He didn't stop there. Legere promised that by the end of 2015, T-Mobile's LTE coverage area would expand to 300 million, and that the carrier would "go toe-to-toe with Verizon's network almost everywhere ... and win." 

All signs are pointing to Legere making good on his promises: T-Mobile's network now covers 304 million people, compared to Verizon's only slightly larger 308 million. 

And new data from OpenSignal shows that T-Mobile subscribers have LTE coverage available to them 81.2% of the time, compared to AT&T's 82.6% and Verizon's 86.7%.

Source: OpenSignal.

OpenSignal pulled about 376 million data points from more than 181,000 smartphone users and found that T-Mobile's LTE coverage "now nearly matches AT&T in LTE availability and is closing the gap with Verizon."

T-Mobile is also fighting back against Verizon's marketing, which still claims that T-Mobile lags far behind Verizon's LTE coverage. A recent T-Mobile press release noted that its LTE network covers 98% of the people that Verizon's covers, has more LTE towers than Verizon, and that the carrier has doubled its LTE coverage over the past 12 months. T-Mobile recently shot back with its own ad that calls out Verizon for using outdated network information (see below). 

But it's not just T-Mobile's LTE coverage that's gotten impressive. The carrier has also managed to provide its customers with LTE speeds that surpass Verizon's. 

Speed matters
T-Mobile said in 2015's third quarter that it's average LTE download speeds had surpassed Verizon's for the past seven consecutive quarters. OpenSignal's data appears to concur, though Verizon is starting to catch up.

Source: OpenSignal.

T-Mobile's average LTE download speed was 12.3 Mbps (megabits per second), while Verizon's was 12 Mbps, according to OpenSignal. While those numbers may be a statistical draw, they still show the strength of T-Mobile's LTE network, which, just a few short years after it was launched, can compete alongside, and in many cases outperform, that of the nation's largest carrier.

The payoff
It's not just industry watchers who have noticed the carrier's transformation. Customers have flocked to T-Mobile as a result of its improvements. The carrier added 2.3 million total net customers in Q3 2015, which was its 10th consecutive quarter of net adds over 1 million.

With 60 million subscribers, T-Mobile still falls far short of Verizon's 137 million. But if the carrier continues to pursue subscriber growth with the same energy it devoted to building out its LTE coverage and boosting its network speeds, T-Mobile may eventually be boasting about how it's closing the subscriber gap as well.