OnePlus 9 5G explained — AT&T, T-Mobile and Verizon

The latest phones from OnePlus support 5G — in fact, 5G is right there at the end of the official names of the OnePlus 9 5G and OnePlus 9 Pro 5G. So you'd assume that you'd be able to fire up either one of the new handsets and hop on your wireless carrier's 5G network, assuming that network is available in your area.

The reality is a bit more complicated.

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In the U.S., both the OnePlus 9 and OnePlus 9 Pro work just fine with one carrier's 5G network, not at all with another one's, and mostly with a third now that official support has been clarified. It's a situation that's bound to frustrate would-be buyers of the OnePlus 9 and OnePlus 9 Pro.

Here's what we know about the OnePlus 9 and 5G, as well as our own experiences testing the phone.

OnePlus 9 and 5G: What's inside

Both the OnePlus 9 and OnePlus 9 Pro run on Qualcomm's Snapdragon 888 silicon. That system-on-chip includes Qualcomm's X60 modem, which OnePlus says can deliver faster 5G speeds by using carrier aggregation to combine FDD (Frequency Division Duplex) and TDD (Time Division Duplex) spectrum usage techniques. What that means is that either OnePlus 9 model should be able to work with the latest 5G networks wireless carriers are building both now and a few years into the future.

But there's more to 5G connectivity than just a phone's modem. A smartphone also needs to support the same bands used by wireless carriers. And in the case of the new OnePlus 9 models, a check of supported bands reveals a different level of support for each U.S. phone carrier.

OnePlus actually includes this information on its website. Go to the OnePlus 9 preorder page (or the OnePlus 9 Pro preorder page if that's the model you prefer), and click on Check Carrier compatibility. You'll see a list of supported bands for AT&T, T-Mobile and Verizon.

OnePlus' list shows extensive 5G band support for T-Mobile as well as support for the 5G bands Verizon uses. There's nothing listed for AT&T.

OnePlus 9 and 5G: What networks are supported?

Put another way, if you buy a OnePlus 9 or OnePlus 9 Pro, it will work with T-Mobile's 5G network. (That's to be expected, as T-Mobile is selling the phone directly, with pre-orders underway in advance of the phone's April 2 arrival at stores.) At launch, OnePlus says that the phone will only work on the LTE networks of AT&T and Verizon.

That makes sense for AT&T since neither the OnePlus 9 or OnePlus 9 Pro supports that carrier's 5G bands. But what about Verizon, since the OnePlus 9 phones do work with that carrier's bands? Just after the unveiling of its new phones, all OnePlus could tell us was that it was to working with Verizon to certify the OnePlus 9 and OnePlus 9 Pro on Big Red's network.

That work paid off, as Verizon and OnePlus have subsequently announced that unlocked phones will work on Verizon 5G, though with some caveats. According to the announced 5G support for the OnePlus 9, the Pro version of the phone will work with both the nationwide 5G networks as well as Verizon's fast Ultra Wideband installations in more than 60 cities. The OnePlus 9 apparently just works with the nationwide network, but not Ultra Wideband.

That squares with our experience testing the phones. My colleague Jordan Palmer was able to connect to Verizon's nationwide 5G network when he was testing the OnePlus 9 Pro. That's the more far reaching Verizon 5G coverage that's built on lower spectrum and, as a consequence, features slower speeds than you might expect from 5G. We weren't able to test the OnePlus 9 Pro on Verizon's faster Ultra Wideband network.

I tested the OnePlus 9 using a T-Mobile SIM card, and I had no problem connecting to that carrier's 5G network whenever it was available. Of course, the speeds I got on T-Mobile 5G were actually slower than other carriers' LTE speeds in that same area. That's the reality of 5G at this point, though.

OnePlus 9 and 5G: Outlook

When a major flagship phone like the OnePlus 9 comes out, the question "will it work with 5G" should yield a simple yes/no answer, not a furrowed brow and a litany of caveats.

Phone carriers and device makers deserve credit for the progress they've made on 5G. But making phone compatibility a crystal clear part of the phone buying experience is essential if people are to be convinced that the 5G future has arrived.