How secure are Threema calls?

Threema calls are as secure as Threema messages. Just like Threema messages, voice calls and video calls are end-to-end encrypted. The call connection is established using Threema messages in the background; therefore, Threema calls are just as trustworthy as chats, and the same verification levels apply.

Instead of a phone number, the Threema ID is used as unique identifier. This allows you to make end-to-end encrypted voice or video calls without disclosing your phone number.

Learn more about Threema calls here.