T-Mobile’s 5G network won’t launch in full until the second half of 2019 because phones aren’t ready yet, according to CNET, which spoke with T-Mobile’s chief technical officer about the delay. That’ll put T-Mobile at least a few months behind Verizon, Sprint, and possibly AT&T (which already has a limited 5G launch) as well.

T-Mobile has been cagey about its 5G launch date: this time last year, the company indicated that it would have 30 cities with 5G by the end of 2018, with phones launching in early 2019. It’s continued to indicate 5G phone launches within the first or second quarter of the year, but evidently that plan has changed.

mmWave 5G will be around earlier, but in limited availability

The problem is, there aren’t any phones yet that fully support T-Mobile’s 5G network, the carrier told CNET. The initial wave of 5G phones don’t take advantage of the main chunk of airwaves that T-Mobile is using to deploy 5G, and without that support, they just won’t be very useful.

A T-Mobile spokesperson said it wasn’t accurate to say the company is delaying its 5G launch until later this year, because T-Mobile will still be launching 5G millimeter wave installations. But there’ll be few locations that support millimeter wave, and because millimeter wave has a very short range, their reach will be quite limited.

Neville Ray, T-Mobile’s CTO, also said in a tweet that it was “wrong” to characterize this as a delay. But he acknowledged that the second half of the year is “when it gets more meaningful” for T-Mobile’s 5G network.

That seems to be why Ray initially told CNET that, despite mmWave 5G phones launching, the carrier won’t necessarily be promoting 5G until later in the year. For instance, T-Mobile will sell Samsung’s Galaxy S10 5G, but Ray seemed to suggest that T-Mobile may not won’t emphasize the phone’s availability because it doesn’t fully support the network.

So it sounds like you will be able to get a 5G connection on T-Mobile in the first half of the year, you just won’t be able to make much use of it. Because of that, T-Mobile appears to be planning on saving its marketing power for later in the year, when it can sell a phone that’ll give customers a 5G experience in more than just the small number of areas supporting millimeter wave.

T-Mobile’s announcement of a 5G launch delay comes just hours after Sprint said it would launch 5G in May. T-Mobile and Sprint are still trying to get their merger approved by US regulators, in part by arguing that it’ll be necessary to quickly deploy a strong 5G network. T-Mobile’s delay doesn’t exactly speak to deployment problems, though: it’s more that T-Mobile wasn’t able to convince hardware partners to build the antennas it needed right away. But it seems like that’ll happen soon enough.

Update February 25th, 11:40AM ET: Updated this story’s headline and added comment from T-Mobile to clarify that the 5G launch is not being entirely delayed, because mmWave will be available earlier.