Telephone numbers within México City are eight digits, the first digit of the local phone number is always 5. México City's telephone system is rapidly improving by being replaced with new digital lines. Some of this improvement is also due to numbers changing. As elsewhere in the country, the telephone company changes numbers without informing the telephone owners or the information operators. Business telephone numbers may be registered in the name of the corporation, which may be different than the name of a hotel or restaurant owned by the corporation. Unless the corporation pays for a separate listing, the operator uses the corporate name to find the number. The local number for information is tel. 040, and you are allowed to request three numbers with each information call.

To call into Mexico, the country code is +52 then the area code is 55 then the 8 digit phone number. If you want to make a Long Distance call out of Mexico, dial the prefix 01 for national calls followed by the area code. If you are making an International Long Distance call, you must dial 00 followed by the country code, in example if you're calling the U.S. you should dial 00+1 and the area code, if you're calling the U.K., dial 0044 and the area code, and so on.

Coin-operated phones are often vandalized, prepaid Ladatel card-only Telmex phones have replaced most of them. Ladatel cards are usually available at pharmacies and newsstands near public phones. They come in denominations of 30, 50, and 100 pesos. Long-distance calls within Mexico and to foreign points can be very expensive.

Monthly line rental includes 100 free Local Calls. Thereafter, local calls are charged at a fixed rate, which varies depending on the plan. The tariff is per call regardless of the length of the call. Calls are rounded up to the nearest minute. Monthly Rental of the telephone costs about MX$167.

Beware of scams, which are plentiful. Be careful when you buy cards on the street, as many vendors will try to switch the card denominations, take advantage of the exchange rate (if your paying in dollars), cheat you with a shortchange or just overcharge you for the cards. Phone calls from your hotel may also be extremely expensive. Another common con are the phones that advertise "TO CALL LONG DISTANCE TO THE USA & CANADA, SIMPLY DIAL 0", usually on the front of businesses. The writing is in black and USA is in blue letters with CANADA in red letters. The phones are put there by a private phone company and are ridiculously expensive.

Averages prices range, but for a basic idea:

• Local Calls (Cost per call in excess of 100) - MX$1.48
• Domestic Long Distance Calls (/Min) - MX$1.32/$3.00
• Calls to USA/Canada (/Min) - MX$5 - MX$12
• Other International Calls (/Min) - MX$9 - MX$20
• Local Calls to Mobile Phones (/Min) - MX$2.03
• Domestic Long Distance Calls to Mobile Phones (/Min) - MX$3.48

There are several important numbers to make note of: