How can I call the US from Thailand after buying a SIM card?

To call the US from Thailand after buying a SIM card, you have several options. If you want to make a direct call, remove the leading '0' from the US number, and replace it with '+1' or '001-1' along with the area code. However, it's often cheaper to use internet-based applications like WhatsApp, Skype, FB Messenger, or Viber that allow free calls if you have a WiFi connection. Some users also recommend calling apps such as Mytello or Dialpad for more reliable calling options. Always ensure your recipient can also use these apps if you're opting for internet calls, as direct dialing can incur high charges.