Can I Use My Old SIM Card on My New Phone? Flor H. Follow Answer This depends on a few factors. If you are switching to a new phone, please contact Republic Help to confirm the SIM card you have will work with a new phone. Article Created From 1272759 Related articles If I Get a New Phone Will I Need a New SIM Card? How to Change Phones and Keep Your Number Unable to Activate Replacement Phone Using Old SIM Card Republic Wireless Phones Why Am I Paying for a Service Plan when I Am Activating Phone as a Replacement?