Yes, most US cell phones will work in the Dominican Republic if they support GSM networks and the necessary frequency bands. For example, if you connect to Claro Mobile, you need to check if your phone supports their frequency bands: 2G (1900 MHz network). 3.5G (850 MHz network). 4G LTE (1700 MHz - 2100 MHz). Also, check with your carrier regarding roaming fees or whether you could use a local SIM or eSIM.