Tello is in the process of transitioning from running over Sprint’s network to running over T-Mobile’s network. New subscribers will receive coverage from T-Mobile’s network by default. Long-standing subscribers’ service may run over Sprint’s legacy network, but these subscribers can opt to switch to T-Mobile. Eventually, Tello will migrate all of its subscriber base to T-Mobile’s network.
Tello’s T-Mobile-Based Coverage
Tello’s GSM service runs over the T-Mobile network. In all likelihood, Tello, like many MVNOs, is contractually prohibited from explicitly advertising that it offers service over T-Mobile’s network.
Here’s what the coverage map looks like for Tello’s GSM service:
For better information about coverage at your location, I suggest exploring Tello’s interactive coverage map. On the interactive map, you can zoom in to see more detailed coverage information.
Tello’s coverage vs. T-Mobile’s coverage
Tello’s GSM coverage map looks quite similar to T-Mobile’s own coverage map:
I expect small coverage differences exist because Tello does not have access to all of T-Mobile’s roaming partners.
Tello Coverage For Legacy Subscribers
Tello subscribers that signed up prior to mid-January of 2021 may still receive service via Sprint’s network. Tello plans to offer Sprint-based service until at least mid-2021. While subscribers on Sprint’s network will eventually be required to migrate to T-Mobile, those who want to switch networks sooner can opt to do so.
I took snapshots of coverage maps for Tello’s Sprint-based service in late 2020. Here’s the map for voice service coverage:
Tello’s map for data coverage looked a bit different:
The maps may no longer be accurate. Sprint and T-Mobile merged in 2020. While Sprint’s network still exists, it’s gradually being decommissioned. Service quality on Sprint’s network may degrade as Sprint’s assets are repurposed to improve T-Mobile’s network.
You can view interactive versions of the coverage maps for Tello’s Sprint-based service by going to Tello’s coverage page then clicking “View cdma” on the lower right of the web page.
While Tello is distinguishing between the networks it runs over by calling one network “CDMA” and the other “GSM”, the distinction is a bit misleading. As a detail in a blog post, today’s networks are primarily LTE networks. LTE is not GSM or CDMA.
Last updated: June 2021