International Access Codes are also used to select the operator. All are starting with 00 while the third number is identifying the operators gateway. Currently there are 3 active codes:

1. Gateway 1 (MPTC or Telecom Cambodia) - 001
2. Gateway 2 (Royal Telecam International) - 007
3. VoIP Gateway - 008

All other combinations are reserved for this purpose only.^[1]

To dial a land line in Cambodia all over the country, the format is Area Code + Phone Number. The area code is 3 digits long, followed by a 6 or 7 digit phone number.

Calls made from outside Cambodia must omit the prefix 0. Therefore, to call a land line number in Phnom Penh from other countries, dialing begins with +855 23 followed by 6 or 7 digits.^[2]

^[3] Area codes starting with 02

1. Phnom Penh - 023
2. Kandal - 024
3. Kampong Speu - 025
4. Kampong Chhnang - 026

Area codes starting with 03

1. Takeo - 032
2. Kampot - 033
3. Sihanoukville - 034
4. Koh Kong - 035
5. Kep - 036

Area codes starting with 04

1. Kampong Cham - 042
2. Prey Veng - 043
3. Svay Rieng - 044

Area codes starting with 05

1. Pursat - 052
2. Battambang - 053
3. Banteay Meanchey - 054
4. Pailin - 055

Area codes starting with 06

1. Kampong Thom - 062
2. Siem Reap - 063
3. Preah Vihear - 064
4. Oddar Meanchey - 065

Area codes starting with 07

1. Kratie - 072
2. Mondulkiri - 073
3. Stung Treng - 074
4. Ratanakiri - 075

Likewise to call mobile phones from land line or other mobile phones, domestic dialing begins a 0 followed by 8 or 9 digits.^[3]

Mobile numbers in Cambodia take the form: 0TT-AXX-XXXY.

The first two numbers after the leading 0 or 'TT' in the example above identify the operator. For example, 010 234 567 is an example of a 9 digit mobile number from Smart. 088 234 5678 on the other hand is an example of a 10 digit mobile number from Metfone.

The 3rd digit after the leading 0 or 'A' in the example above must be between 1 and 9.^[4] Normally this value is between 2 and 9 which allows a value of '1' to be used for mobile phones which are roaming in Cambodia. However some operators such as Mobitel are using a '1' in this range to extend their number ranges for certain popular prefixes. For example, 012 123 4567 and 092 123 456 are valid mobile numbers in Ca

'X' can take the values 0 to 9 and 'Y' is an optional extra digit which is used by some operators.

Most mobile numbers are 8 digits long (excluding the leading 0), however some operators are now using 9 digit numbers. 0882345678 is an example of a valid 9 digit mobile number.+85592662075

Calls made from outside Cambodia must omit the prefix 0. Therefore, to call a mobile number in Cambodia from other countries, dialing begins with +855 1, +855 8, or +855 92662075/9 etc.

• Telecommunications in Cambodia