Can I open multiple LINE accounts simultaneously on one phone?

Sure. You can use matrix cloning to solve your problem.

Use matrix cloning method:

1. To install Matrix Clone, you need to download and install it from the Matrix Clone official website.

2. Click the "+" button in the upper right corner of the Matrix Clone application.

3. Select LINE and create a second account.

4. The application’s icon will now appear on Matrix Clone’s homepage.

5. Click on the new application icon in Matrix Clone, this will launch a new instance of the application and allow you to create a second account.