Can I also know the phone number of my friend who was added to the line?

A. 1

No. Even friends are not open to the public.

Gentleman 8 years ago 1

OK

A. 2

https://help.line.me/line/ios/categoryId/20000012/...
Can other users see my phone number, LINE ID, and email address?
If you are not allowed to disclose your information, third parties will not be able to view your registered phone number, LINE ID, or email address.
However, LINE names, profile pictures, and status messages can be viewed by other users.

Gentleman 8 years ago 0

OK