A trunk prefix is a digit sequence to be dialled before a telephone number to initiate a telephone call for the purpose of selecting an appropriate telecommunications circuit by which the call is to be routed.

Making a domestic (national) telephone call usually requires the dialling of a single or two-digit national trunk prefix preceding any area codes and the destination subscriber number. In most countries, the trunk prefix is 0.

For international telephone calls, the national trunk prefix is not dialled; instead, an international trunk prefix (or "+") is typically required, followed by the destination's country code.

Example 

This example assumes that a call is to be made to a customer in the Australian state of Queensland with the local number 3333 3333 and the area code 7.

A caller from outside Australia must dial the international call prefix of the originating country and the country code (61 for Australia), then the area code (7), and then the local subscriber number. Therefore, a caller in the UK must dial 00 61 7 3333 3333, while a caller in the US must dial 011 61 7 3333 3333.

Calling inter-area (within Australia) (e.g. from Western Australia with area code 8), a caller need not dial an international trunk prefix or a country code. Instead, the caller must at least dial the Australian trunk prefix (0) followed by the area code (7) and then the local subscriber number: 07 3333 3333. Calling from within the Queensland (7) area, a caller need only dial the telephone number: 3333 3333.

However, since the early 21st century, the majority of telephone systems worldwide can recognise the area of origin of the call, its direction and destination to facilitate communication faster. If the full international number is used, then this full international number may be dialled from nearly any telephone within a recognisable landline or mobile network. This has become particularly vital for users of mobile phones.

When conducting business, e.g., for display on business cards or stationery, a telephone number is represented as +61 7 3333 3333, and includes only the digits that must be dialled internationally. The plus sign indicates that an international trunk prefix is first dialled and, therefore, a country code follows.

Countries using national trunk prefixes

Countries that use 0 as national trunk prefix

Africa 

 Egypt
 Morocco
 Kenya
 South Africa
 Sudan
 Tanzania
 Rwanda
 Nigeria
 Libya

South America 

 Argentina
 Brazil
 Paraguay
 Peru
 Venezuela

Asia 

 Afghanistan
 Bangladesh
 Cambodia
 China (landlines only)
 India (landlines only)
 Indonesia
 Iran
 Israel
 Japan
 Jordan
 Laos
 Malaysia
 Myanmar
 North Korea
 Nepal
 Pakistan
 Philippines
 Saudi Arabia
 South Korea
 Sri Lanka
 Taiwan
 Thailand
 Vietnam
 United Arab Emirates

Europe 

 Albania
 Austria
 Belgium
 Bosnia and Herzegovina
 Bulgaria
 Croatia
 Finland
 France
 Georgia
 Germany
 Ireland
 Moldova
 Montenegro
 Netherlands
 North Macedonia
 Romania
 Serbia
 Slovakia
 Slovenia
 Sweden
 Switzerland
 Turkey
 Ukraine
 United Kingdom

Oceania 

 Australia
 New Zealand

Countries that use 8 as national trunk prefix 

 Azerbaijan
 Belarus
 Kazakhstan
 Lithuania (change to 0 planned)
 Russia (change to 0 planned)
 Turkmenistan
 Uzbekistan

Countries that use other trunk prefixes 
The number next to a country denotes its national trunk prefix.

 Mexico – 01
 Mongolia – 01 or 02
 Hungary – 06
 North American Numbering Plan countries – 1

Countries that no longer use a national trunk prefix 

 Bolivia
 Chile
 Cyprus
 Czech Republic
 Denmark
 Estonia
 Greece — the prefix 0 was replaced by 2 for landlines and 6 for mobile phone numbers, which are now part of the number
 Italy — the leading 0 is dialled both within and from outside Italy, because 0 is now part of the number and not the trunk code
 Latvia
 Luxembourg
 Malta
 Monaco
 Nepal
 Norway
 Oman
 Poland
 Portugal
 San Marino — the leading 0 is dialled both within and from outside Italy, because 0 is now part of the number and not the trunk code
 Spain
 Uruguay
 Vatican City — the leading 0 is dialled both within and from outside Italy, because 0 is now part of the number and not the trunk code
 Singapore

See also 

 Subscriber trunk dialling

References

External links 

Glossary — World Telephone Numbering Guide.

Telephone numbers