*This article is only compatible with the KnowRoaming Global SIM Sticker.
Verizon and Sprint use a technology called CDMA for their SIM cards. Currently, KnowRoaming is only compatible with GSM SIM cards. So the short answer is we do not support CDMA (Verizon and Sprint) SIM cards at this time.
But my phone is enabled with GSM AND CDMA bands!
Most of the new smart phones that Verizon and Sprint offer their customers are built to use GSM and CDMA bands. This is because the vast majority of carriers worldwide use GSM so if someone using a CDMA-only device travels abroad they would have a very hard time connecting to a foreign network.
CDMA SIM cards transfer electrical signals quite differently than GSM SIM cards do. Only in the last few years have CDMA carriers even started using SIM cards (mostly for 4G/LTE purposes).
In short, the incompatibility with our current SIM sticker is that it isn't able to properly transfer those electrical signals from your CDMA SIM card to your phone while at home in the US. So the KnowRoaming SIM sticker would work perfectly fine while abroad but the issue is you wouldn't be able to use your Verizon/Sprint service while back at home. So that's why we are not compatible with CDMA SIM cards at this time.
Good news though! We offer a Global SIM Card that works as a great alternative for anyone who uses a CDMA SIM card at home. The SIM Card takes advantage of the exact same voice and data rates as the SIM Sticker and costs less than the SIM Sticker does.