Iphone 16 unlocked?

@Alohabuffy Since you bought directly from Apple your phone is unlocked. It's only when you purchase from a carrier with installments or a promotion will they lock until paid off. To verify Go to Settings > General > About, and look for the "Carrier Lock" section. If it says "No SIM restrictions", your iPhone is unlocked.

Howdy Alohabuffy. You technically would not need to modify the SIM specifics. We have our Global Travel Pass that allows you to pay a daily flat rate for data when you travel in over 215 countries. This pass includes 5 GB of high-speed data per day. After 5 GB of data is used, data is available at 3 Mbps speeds until a new pass is started. With 3 Mbps, you can still check email, browse online, send messages, and more.  The data you use while abroad will not count toward your By the Gig or Unlimited data option. 

How do I add Global Travel Pass to a line?
To add Global Travel Pass to any phone line on your account through the Xfinity app:

1. Sign in to the Xfinity app.
2. Click the Services tab.
3. Select the Mobile lines and data usage located within the Mobile services card.
4. Choose the phone line you’d like to add the Global Travel Pass to.
   
   • This takes you to the line details screen.
5. Scroll to the Plan Features section, click Get Global Travel Pass, and go through the prompts.
6. You will get a confirmation screen once you have successfully added Global Travel Pass.
7. Make sure your device is enabled for data roaming.
   
   • You must do this through your device’s settings.

To add Global Travel Pass to any phone line on your account online:

1. Sign in to your Xfinity Mobile account.
2. From the Activity page, choose the phone line you would like to add the Global Travel Pass to.
   
   • This takes you to the line details screen.
3. Scroll to the Plan Features section, then click Plan your trip in the section called International Travel.
4. Choose Get Global Travel Pass and go through the prompts.
5. You will get a confirmation screen once you have successfully added Global Travel Pass.
6. Make sure your device is enabled for data roaming.
   
   • You must do this through your device’s settings.