You are new in Germany and are wondering how to get internet and telephone service? A helpful overview in English can be found at:
https://www.justlanded.com/english/Germany/Telephone-Internet

SERVICE PROVIDERS
In Germany, internet and telephone service can be ordered online or obtained from dedicated stores located in most city centres. Nowadays many students opt for a good mobile plan and do not get a landline connection in their apartments. There are four main providers in Germany:

  • T-Home / D1 (www.t-mobile.de)
  • Vodafone / D2 (www.vodafone.de)
  • E-Plus (www.eplus.de)
  • O2 (www.o2online.de)

Bills, correspondence and customer service will usually be in German. The terms and conditions of service agreements should be read carefully. Often, German phone or internet plans consist of an initial 2-year contract and must be cancelled 3 months in advance to avoid an automatic and binding contract extension.

Providers generally require some type of identification, a proof of residency (Anmeldebestätigung) and a bank account. If you have a contract, then the bill is automatically debited each month from your bank account.
Helpful information can be found at:

CONTRACT VS PREPAID SIM
Prepaid phones allow maximum flexibility. You can top up your credit at your convenience. Simply buy a recharge card (Wiederaufladung) that is available at mobile stores and kiosks. The minimum amount that can be recharged is usually 5-10 Euros.

Contracts are less flexible but offer other advantages such as it is payable at the end of each month and lower calling rates apply. When choosing a plan be sure to read all conditions such as the monthly fees (Grundgebühr), the connection cost (Verbindungskosten) and the minimum monthly consumption (Minimalumsatz).
Most SIM cards can be bought in local stores, supermarkets and kiosks. They usually cost around 10 Euros and charge 9 cents per SMS or per minute calling. Most common prepaid SIM cards are:

  • Aldi Talk (Eplus)
  • Otelo (Vodafone)
  • Congstar Prepaid (T-Home)
  • Lidl Mobile / Fonic (O2)
  • Blau (Eplus)
  • Edeka Mobile (Vodafone)
  • Tchibo Mobile (O2)

Helpful information can be found at:
prepaid-data-sim-card.wikia.com/wiki/Germany

CALLS OUTSIDE GERMANY
International calling cards are a cheap and practical way to keep in touch with your family and friends at home. They usually offer the lowest rates available (up to 90% cheaper than normal calls) and can be used from every phone (work, home, mobile and public phones). International calling cards can be obtained in local kiosks. Rates vary and should be checked online. Helpful information can be found at:
www.justlanded.com/english/Germany/Services/Telephone-Internet/International-calling-cards
International calling can also be done via VOIP which uses internet to call.

CALLS IN GERMANY
In Germany, most people will answer the phone by saying their last name instead of a greeting. This may sound harsh or confusing at first but remember that Germans like to get straight to the point. When you want to call somebody you should identify yourself first before stating your request. The following page gives an overview of typical German recorded messages that you may encounter as well as when and how to dial area codes:
www.justlanded.com/english/Germany/Germany-Guide/Telephone-Internet/Calling