Cricket Wireless puts up their own towers.

They also roam on other networks when Cricket service is not available, including, but not limited to, Sprint, MetroPCS, and Verizon Wireless.

Please note: Roaming on some networks can be done at no additional charge, while some networks will cost you. You can pay for roaming by adding money to your Flex Bucket account.

You can definitely roam on Sprint and MetroPCS at no additional charge. You can roam on Verizon Wireless at a rate of 25 cents per minute. There aren't any roaming charges for text messaging while roaming on Verizon Wireless.