Those would be fighting words.
Masayoshi Son, who serves as both the CEO of Japanese carrier SoftBank and chairman of Sprint, railed against the wireless networks in the US as he made the case for why Sprint is poised for a turnaround.
"When I come to the [United] States, this network is not something you should be proud of," he said on Sprint's quarterly conference call with analysts. "It's very, very bad."
This is not the first time Son has employed this argument -- he did it a year ago as he made the case for why he should be allowed to combine T-Mobile with Sprint, a notion that the US regulators quickly squashed. But his appearance on the Sprint call is a signal that he is ready to fully support the US carrier, which he acquired two years ago, and push it to improve the quality of its coverage.
His comments come after Sprint posted improved financial results, but ceded the No. 3 position to T-Mobile, which has outpaced Sprint in growth over the last few quarters.
Son wasn't vague when he leveled his criticisms, calling out Verizon Wireless, AT&T and T-Mobile directly. Japan had the best network, he said. "It's a fact." And Son in particular was skilled at building out a speedy network without a huge amount of expense. It's for that reason he believes that Sprint's network will be "much better very soon," echoing CEO Marcelo Claure's boast that his network will be equal to or better than those of his rivals in two years. Sprint, however, lags behind the other carriers when it comes to network speeds, according to several independent tests.
Verizon defended the state of US wireless service.
"US networks are some of the best in the world, and Verizon has been the leader in rolling out the fastest and most reliable network technology to millions of Americans," said Mike Haberman, vice president of network support. "In order to have the network we have today, the right expertise in building networks and significant investment are required."
T-Mobile CEO John Legere responded -- in his usual way -- with a series of tweets.
"Does that make Sprint's network 'VERY, very, very bad' or just completely terrible," Legere said in a tweet.
"It's easy to boast about your network in Japan, @masason. That's 146k square miles, or basically most of California. #notthathard ;)," he said in a follow-up tweet.
AT&T declined to comment.
Does that make @sprint's network 'VERY, very, very bad' or just completely terrible? https://t.co/b07zZCCQ1v
-- John Legere (@JohnLegere) August 4, 2015
Are Son's proclamations true? Japan's wireless networks do rank higher than the US, but not by that much, according to study conducted by wireless data research firm Open Signal. SoftBank runs an average download speed of 13 megabits per second, compared with 10 megabits per second for T-Mobile, which the firm says is the fastest US carrier.
But according to this study, neither Japan nor US is even in the top 10 -- Spain boasts the fastest average speeds, followed by Finland and Denmark. Even with the higher speeds, a smaller percentage of Japanese use features like music or video streaming, according to a study conducted by Recon Analytics.
"Despite not offering the world's fastest download speeds, the United States leads the world in adoption of smartphone services that take advantage of fast networks," the study said.
That's a far cry from Son's thoughts on mobile video bundles in the US: "Before you talk about video bundle over mobile networks, all four carriers have to cure the issue of congestion," he said. "That's more fundamental to basic service."
Son, meanwhile, also acknowledged that he lost confidence in Sprint after regulators shut down his plans to buy T-Mobile, which he argued would have created a more competitive No. 3 player to go up against larger rivals AT&T and Verizon. But over the past few months, he has been "totally refocused" to help Sprint with its turnaround. He added that he's spent every night between 10 p.m. and 2 a.m. working with the engineers to plan out the company's next-generation network.
"I am extremely excited by the turnaround at Sprint," he said.
Updated at 11:31 a.m. PT: To include T-Mobile CEO John Legere's response.