You would like to switch to a different service provider and keep your current phone number? No problem, just take note of the following requirements for a successful mobile number portability.

1. Cancel your current contract and request immediate portability
You should end your current plan in time, so that you don’t have to pay for two phone plans. Once you have cancelled the contract, you can take your phone number to other providers even 120 days before your contract actually ends. If your contract has already ended, you can take your number to another provider within 30 days after the termination date.

Documents to send to your current provider to request the number portability before your contract has actually ended:

Congstar template for an early mobile number portability


2. Cancel your contract and request portability after termination

If you just want to transfer your number to a different carrier after your current contract ends, you just need to send them a letter saying that you would like to retain your phone number while using a different service provider.

Documents to send to your current provider:

Congstar template for mobile number portability after a contract has ended


3. For PREPAID users: Request portability from your prepaid provider

For prepaid users it is a bit easier, you just need to send a letter of request a few days before you are ordering your new plan. Your new service provider will then request the mobile number portability from your old carrier.

Documents to send to your current prepaid provider:

Congstar template for an prepaid mobile number portability


4. Order your new phone plan

Look for your desired phone plan and don’t forget to inform your new carrier that you would like to retain your old number. This needs to be done within the order process. For Congstar this would look like this:

congstar phone number retainment

You need to select “Rufnummer sofort mitnehmen” for an immediate portability and “Rufnummer am Ende der Vertragslaufzeit mitnehmen” for a mobile number portability (MNP) after your contract ended.

The cost of keeping your old phone number is usually 25€, but can not be more than 30,72€. You usually get these 25€ refunded by your new phone carrier.

If you have any further questions, write us an email to

13 Responses

  1. Kiran Kumar

    I have an O2 prepaid SIM now. I want to get it ported to Winsim postpaid contract from O2 prepaid. Please let me know how do I proceed ?


  2. Good day. I’m Uzoma. I have contact with Blau. Which I’m happy it. But have to wait till the end of the contract. I want to know if is possible to transfer my contact and number to another network. Thank you

  3. Hello Ben,
    I am using vodafone call-ya sim card. Time to time I use to recharge for 15 euro. May be every 40 days I recharge for 15 Euros. Now I want to use the same number but with Congster. How to do it? I have no contract with Vodafone (I just bought only the SIM card online). When ever I don’t have enough money in my sim, I use to recharge for 15 Euros.

    • Hello Raj,
      You can read more about mobile number portability here:

      • Hello Ben,
        Just noticed that there is a fee for this. And it is 29.95 Euros. How should I pay this money? I found a similar form on vodafone internet and in that form I notice the following lines:
        Ich möchte die oben genannte CallYa-Rufnummer zum nächstmöglichen Zeitpunkt zu einem anderen Anbieter von Telekommunikationsdienstleistungen mitnehmen. Ich verzichte gegenüber Vodafone auf die Bereitstellung von CallYa-Dienstleistungen ab der erfolgreichen Portierung der Rufnummer zum neuen Anbieter und bin damit einverstanden, dass der dieser Rufnummer zugrundeliegende CallYa-Vertrag zum selben Zeitpunkt endet. Sie können Ihre CallYa-Rufnummer nur unter diesen Voraussetzungen mitnehmen:
        • Die oben eingetragenen Daten müssen exakt mit den bei uns registrierten Daten übereinstimmen.
        • Es darf für die oben genannte Rufnummer kein Wechsel in einen Vodafone-Vertrag mit Mindestlaufzeit
        beauftragt sein.
        • Die Rufnummern-Mitnahme berechnen wir mit 29,95 Euro. Sie sorgen für ein ausreichendes Guthaben auf
        Ihrem CallYa-Konto, bis wir Ihre Verzichtserklärung bearbeitet und den Betrag abgebucht haben. Nach
        erfolgreicher Abbuchung bekommen Sie von uns eine Bestätigung per SMS auf Ihr Handy.
        • Der Auftrag für die Mitnahme oben genannten Rufnummer muss vom neuen Anbieter an Vodafone
        übermittelt werden.

      • Yes, there is usually a fee of around 25€, or as in Vodafone’s case 29.99€. But you usually get the 25€ back from your new provider (as credit). In case of a prepaid card, you pay the fee with your available credit, so you should make sure that you have enough credit available (29.99€ or more) on your sim card.

      • Thanks ben!
        I am curious to know weather calling a congstar to congstar free?
        If yes I plan to buy two sims.

      • No, congstar does not offer this option. You will need to use your included minutes for calls to congstar or pay 9 cents per minute.

  4. What exactly happens in the first scenario: do I get it right that in that case I get the number which I can use with another carrier, but I still need to pay monthly fees to my old carrier until the contract actually expires?

  5. Hi,
    I recently moved to Germany and I started off using a prepaid sim from lycamobile. I was no longer satisfied with their service and decided to take a contract with 1und1. I contacted customer service of 1und1 and I was informed by the agent that it was not a problem. He said 1und1 would do my number porting. He then took my number down, took my personal details, made the contract and told me to call the control center as soon as I get a packet from them and that was it. I just called 1und1 control center now, only to be told that I have to do do the number porting myself, contact lycamobile and pay 30 euros to them. I find this very strange and in total contradiction to what their agent told me before the contract. I have more or less made up my mind to cancel the contract with 1und1 immediately as I find this whole issue to be full of dishonesty. But then I thought I would check online and ask for opinions.

    Best regards.


    • Hi Ola, it is actually not unusual that you have to do the number porting yourself. However, the communication from 1und1 was just bad and dishonest. They should have given you the correct information about the procedure from the beginning. But very often, these agents/salespeople just want to close contracts and tell you everything you want to hear…

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