LINE currently allows only SIM cards directly issued by Docomo, SoftBank, Au, LINE mobile, and some of the MVNOs in terms of Search by ID function.

Due to the law regulation from December 2012, it is necessary to perform age verification to use this function. However, since we do not have a direct contract with LINE to support this function, we cannot help you in this regard. 

Meanwhile, you can still add new friends through different methods:
- SMS/e-mail
- QR code
- Shaking (Furu-furu)