Update, August 5, 2021: The T-Mo Report revealed the shutdown dates for the T-Mobile 2G GSM and 3G UMTS networks.

What you need to know

• Sprint 3G (CDMA) is shutting down on January 1, 2022, followed by LTE on June 30, 2022.
• Most Sprint LTE phones simply need a SIM swap to keep working, and free phones will be available to others.
• T-Mobile 2G and 3G are also planned to be retired.
• T-Mobile will contact customers with incompatible phones.

T-Mobile has been extremely aggressive in gaining access to valuable wireless spectrum for its growing 5G network. T-Mobile purchased Sprint in April of 2020 and was quick to start moving customers with compatible phones over to the T-Mobile network while preparing to shut down Sprint's legacy 3G and LTE networks. This makes sense as operating two networks with a lot of overlap is extremely expensive.

T-Mobile has already taken down portions of Sprint's network, starting with band n41 5G, which has become the foundation of T-Mobile's Ultra Capacity 5G coverage. Most recently, T-Mobile revealed (opens in new tab) the dates that more of the Sprint network will be decommissioned, starting with the 3G CDMA network shutting down on January 1, 2022. Following that, Sprint's LTE network will be shut down on June 30, 2022.

T-Mobile points out that its LTE covers 99% of Americans, and most Sprint LTE phones work with the T-Mobile LTE network with a SIM card swap. Customers' plans will be updated to support T-Mobile's LTE and 5G network if they don't already, so no plan changes are necessary. However, it's possible to save some money by switching to another T-Mobile plan. This includes some of the best cell phones plans you can get.

Besides T-Mobile LTE data support, phones will also need to support VoLTE. This routes phone calls over the LTE network as opposed to using an older 2G or 3G connection. Most people with phones from the last few years are already using VoLTE. T-Mobile points out that phones that don't support VoLTE won't be able to make calls after the network shuts down, including emergency 911 calls.

Affected customers have already been notified or will be contacted about the transition. Customers with phones that won't work on the new network "can upgrade to a new device at no cost," but T-Mobile also recommends customers check their upgrade eligibility. Customers can also consider buying any of the best Android phones unlocked so they can easily change carriers if they find the T-Mobile network doesn't fit their needs.

T-Mobile also revealed that its own 2G GSM and 3G UMTS networks will be shut down but did not give a specific date. The T-Mo Report has internal documentation for employees that sets the shutdown date for 3G UMTS at October 2021, which is only a couple of months away. 2G is set to shut down in December 2022.

Samsung Galaxy S21

Unlocked with full support for T-Mobile's LTE and 5G network
The Samsung Galaxy S20 is one of the best 5G phones you can get, with great support for low-band, mid-band, and mmWave 5G.