Straight Talk Wireless subscriber identity module cards compatible with Verizon Wireless GSM phones are available through the Straight Talk Wireless website or through retailers such as Walmart. These cards are compatible with select Verizon phones that have been unlocked from the Verizon network.
Some older Verizon phones are based on a networking technology known as CDMA that is not compatible with the GSM networks used by Straight Talk Wireless. Some of these phones may feature SIM card slots, especially if they were sold as part of Verizon's Global Ready phone program, in which case they may be compatible with Straight Talk. Most newer phones that use 4G connections use the GSM standard and are compatible with Straight Talk's SIM cards for GSM phones.
Verizon phones must be unlocked to use SIM cards from another service provider, but as of April 2015, Verizon sells most of its 4G LTE devices already unlocked for use with any carrier. 3G prepaid Phone-in-a-Box phones are locked to the Verizon network for 12 months after purchase, but most of these devices are unlikely to be compatible with Straight Talk Wireless. Global Ready 3G phones are locked to Verizon Wireless's network as well, but they can generally be unlocked using an unlock code, depending on the specific model.