Glossary

Number porting

Number porting means taking an existing phone number along from one telephone provider to another.

Also: number portability, porting a phone number

This entry describes the situation in Germany, where keeping your number when switching providers is governed by the Telecommunications Act (Telekommunikationsgesetz, TKG). The new provider submits the porting request, and the previous one releases the number on an agreed date. The details of the line holder have to match exactly. Geographic numbers stay tied to their area code. Other countries have their own rules and procedures.

For an AI phone assistant, porting is rarely necessary. Call forwarding or a SIP trunk is usually enough, and the existing contract stays unchanged. Porting is worthwhile when the whole line is moving anyway. It takes longer than forwarding and cannot be reversed at short notice, so plan a date outside peak hours.

At Call0

You do not have to change your number for Call0: you forward it or use a Call0 number.

Source: Section 59 of the German Telecommunications Act (TKG), in German

This entry explains the general principle, with a focus on German and EU law, and is not legal advice. For your case, the text of the law and the advice of a qualified professional apply.

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As of: 6 October 2026