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Phone communications in other countries

A variety of voice communication options are available you while you travel abroad, including using your own cell phone, voice over Internet protocol (VoIP) service, purchasing a SIM card, and purchasing or renting an international cell phone.

Cellular Phones

  • Ask your service provider if your phone will work overseas. If not, obtain one that is specifically designed to work abroad. The ability to use your own phone outside the U.S. depends on what network standard your cellular carrier uses. Click here for a list of U.S. cellular carriers and the network standards they use.
  • If you have a GSM (Global System for Mobile) compatible phone, it will probably be able to acquire a signal in your destination country. International roaming rates will apply. Countries outside of the Americas use different GSM frequency bands than those used here, so you will need a tri- or quad-band phone to receive service in those countries (refer to the list of frequency bands below).
  • If you have a CDMA (Code Division Multiple Access) compatible phone, it may not be able to acquire a signal in your destination country when traveling outside the Americas. Your carrier should be able to rent you a GSM compatible phone if this is the case. Some CDMA smartphones may be able to operate in GSM-only countries. Contact your service provider for more information.
  • A quad-band type GSM phone can operate within four different frequency bands:
    • 850 MHz (U.S., Canada, Latin America and Brazil)
    • 900 MHz (Africa, Europe, Brazil, Australia, much of Asia except Japan and South Korea)
    • 1800 MHz (Africa, Europe, Brazil, Australia and Asia)
    • 1900 MHz (U.S., Canada, Latin America and Brazil)
  • Your existing GSM phone may support quad-band communications ( most modern smartphones do ) or it may be only dual- or tri-band compatible. Dual-band (850/1900 MHz) U.S. phones will not work in any of the 900 or 1800 MHz regions listed above and tri-band U.S. phones will often have low signal strength in these regions.
  • Compatible U.S. cell phones will work in most urban areas, but coverage in other areas may be limited or non-existent.
  • U.S. GSM carriers often provide an “international calling” option that can be added to your plan before you depart and removed when you return. This option allows you to pay less for international roaming than you would without it.
  • In many countries, data plans cost significantly more than in the U.S. To avoid using your data plan while abroad, consider canceling it before you leave and reactivating it upon your return. Many smartphones also allow you to disable data roaming in order to avoid unwanted data charges. Contact your service provider prior to your departure to research the types of plans and pricing available.
  • CDMA carriers often provide a “world phone” rental service to their customers. If not, an international cell phone can be rented from an independent company.
  • Most packages include the phone, phone number, charging accessories, a user guide and a SIM (Subscriber Identity Module) card with initial airtime minutes.
    • Cost usually includes weekly, daily, and/or monthly prepaid airtime fees.
    • The phone must be shipped back to the provider when you no longer require the service.
    • Based on the length of your stay, consider purchasing an international phone and SIM card if it will provide cost savings.
  • More information can be obtained from your cellular carrier or from the websites of international cell phone vendors: 
    One SIM Card: Home
    One SIM Card: Rent or Buy? 
    Cellular Abroad: Frequently Asked Questions
  • SIM cards are portable memory and identification chips used in all GSM-type cell phones and some CDMA smartphones. SIM cards store subscriber-specific information used to authenticate users on the service provider’s network.
  • GSM users can switch to a new phone by simply sliding the SIM card out of the old phone and into the new one, provided the new phone is unlocked .
  • If your phone was purchased at a subsidized price through your cellular carrier, it will most likely be locked so that it can only function with SIM cards from your specific service provider . To use a pre-paid SIM card for your U.S. GSM phone, it must be unlocked.
  • Certain CDMA smartphones may also be able to function with foreign pre-paid SIM cards.  Contact your carrier for further details.
  • If you purchase a pre-paid SIM card:
    • You may be required to present ID photos, copies of your passport/visa and possibly proof of residence.
    • You will be assigned a phone number randomly by the service provider.
    • You may pay for service in regular increments (like $5.00 or $10.00) with the   voice and data transmission limits increasing with the cost of the card.
    • You may lose minutes not used by the expiration date, e.g., minutes may expire if not depleted within 90 days.
  • A Global System for Mobile (GSM) phone, or "world phone," enables international roaming between mobile phone operators. Subscribers of one service can use their phones on many other services around the world.
  • A quad-band phone is a GSM phone that can operate in four different frequency bands:
    • 850 MHz (U.S./Canada/Latin America/Brazil)
    • 900 MHz (Africa/Europe/Brazil/Australia/much of Asia except Japan and South Korea)
    • 1800 MHz (Africa/Europe/Brazil/Australia/Asia)
    • 1900 MHz (U.S./Canada/Latin America/Brazil)
  • GSM phone is defined as “locked” when software settings prevent the device from using other cellular carriers. A locked phone will only recognize a SIM card from a particular carrier while an unlocked phone can recognize SIM cards from a variety of carriers. 
  • Renting or purchasing an unlocked phone will allow you to use pre-paid foreign SIM cards while traveling. In many countries, you have the option of purchasing an unlocked device and then choosing your service provider.
  • Unlocked phones can be purchased from the following vendors:
  • In some cases, you might also be able to unlock your own GSM phone by obtaining an unlocking code from your carrier. Contact your service provider for further information on their policies.
  • Disposable phones can be purchased in the destination country for the purpose of making local calls.

Calling to the U.S. from a foreign country

  • To dial a U.S. number from a foreign number:
    • Enter the origination country exit code (or the plus (+) sign if using a cell phone, dialed by holding down zero (0)).
    • Enter the destination country code.
    • Enter the telephone number.
  • To dial a foreign number from within the same foreign country:
    • Enter the Trunk Code of the country.
      • Example: the U.S. trunk code is “1.”
    • Enter the destination country code.
    • Enter the telephone number.
  • To dial a foreign number from a U.S, number:
    • Enter “011.”
    • Enter the destination country code.
    • Enter the telephone number.
  • For more information about international calling, refer to how to call abroad.