AT&T’s postpaid service offers domestic roaming in some areas the where prepaid subscribers will not have any service. While I haven’t found anywhere where AT&T clearly lists the areas where postpaid subscribers can roam and prepaid subscribers cannot, a lot can be figured out by exploring AT&T’s coverage map which allows users to distinguish between coverage with postpaid service and coverage with prepaid service.
Looking at the entire U.S., a few differences in coverage are obvious. Here’s a snapshot of the postpaid coverage map from AT&T’s website on 5/30/2019:
Here’s the prepaid coverage map:1
Arrows indicate some areas places where coverage differs between prepaid and postpaid service. Within the United States, the differences largely appear in sparsely populated parts of the West. However, AT&T’s maps may mask some details. When zoomed-out, Michigan appears completely blue. However, if I zoom into a section of Michigan, I can see that a decent-sized part of Huron National Forest is without coverage (prepaid or postpaid).
Sometimes zooming in on the same areas on both maps can reveal differences in prepaid and postpaid coverage. For example, Oklahoma appears totally blue when zoomed-out on both the prepaid and postpaid maps. If I zoom in on south-eastern regions of Oklahoma on the prepaid map, I see some areas without coverage:
In the postpaid map, many of those areas appear in orange (indicating off-network coverage is available):
If there are specific areas where you want to know whether AT&T’s prepaid and postpaid coverage differs, I suggest zooming in on them on AT&T’s coverage map.
While AT&T’s prepaid service appears to offer less roaming access than AT&T’s postpaid service, the prepaid map makes it clear that prepaid subscribers have some off-network coverage.
Roaming restrictions
AT&T subscribers may be restricted in their use of non-AT&T networks. An article on AT&T’s website about domestic roaming states the following:2
- The Off-Network data restriction won’t impact voice calls, text, or Wi-Fi access.
- We’ll send a text message informing you reached 400MB while Off-Network.
- International and domestic off-net (roaming) data usage may be at 2G speeds.
- Once you travel back to our network, data access will resume.
