A reader, Ashley, writes…

I just bought a used Straight Talk Samsung Galaxy s3 with no SIM card. I am already using a Straight Talk phone, but it doesn’t use a SIM card. I found where I can order one on the Straight Talk site, but I don’t know which one it needs. There are only four listed and none of them have the s3 listed in their description. I tried a live chat with an associate, but she was absolutely no help. Do you happen to know which size SIM card I need?

Hi Ashley,
Your Straight Talk Samsung Galaxy S3 phone may or may not need a SIM. If you do need a SIM, pick the SIM for the network you need to use and the size that fits your phone. The S3 uses a micro SIM.

As for which network to choose… Straight Talk does not own their own mobile network, they lease service from AT&T, TMobile, Verizon, and Sprint. Your Straight Talk phone will use one of these networks. I think most Straight Talk Galaxy S3 phones use Straight Talk’s Sprint and Verizon networks. You can figure out which network your phone is compatible with by the model number of the phone. What is it? Check the phone’s settings or under the battery cover.

Straight Talk’s Sprint and Verizon networks do not use SIMs. You should just need to activate the phone using the MEID number found in the phone’s settings. You may have a problem if the phone is still associated with the previous owner’s account.

If your Straight Talk phone is a Sprint model, it may get 3G data service when you activate it. Several readers have told me that they get 4G LTE service on the Sprint network (faster than 3G) after calling Straight Talk and having them enable 4G LTE service for the phone.

If your Straight Talk phone is a Verizon model, it will only get 3G data service. Like the Sprint phone, you should just need to activate the phone using the MEID number in the settings. You may have a problem if the phone is still associated with the previous owner’s account. Recently Straight Talk has started offering Bring Your Own Phone customers with Verizon phones use Verizon’s 4G LTE network, which does require a SIM. Unfortunately, they don’t seem to be letting customer’s with Straight Talk phones upgrade to 4G LTE service.

If your Straight Talk Galaxy S3 phone is a GSM model for the ATT or TMobile network, you’ll need a SIM card. When activated, your phone should get 4G LTE service if its available in your area. Straight Talk may have sold the phone with either their ATT or TMobile SIM, but you should be able to just buy the SIM for the network you prefer. Most people usually just choose the network that works best where they use their phone.

I understand this is somewhat confusing, so just let me know the model number of your phone.

Regardless of which Straight Talk network you are on, you should be able to transfer your service from your current Straight Talk phone to your new phone. You can call Straight Talk and have them do this or do it yourself on line. Log into your account and add your phone to your account, then follow the steps to transfer your service to the new phone. I wrote an article about this and the steps should be similar. See Transferring Your Existing Straight Talk Service to a New Straight Talk Phone or SIM