It is an international telephone service (international direct dialing, IDD) by dialing access 001 from every mobile phone and fixed-line telephone network. Simple making call, the best call quality, showing every calling number (CLI), without disturbing noise, and non-delayed voice signal.

Call charge (tariff)

Please select destination country


- Minimum call charge is 1 minute. The following minutes count as units at 6 seconds per unit. A sub-unit fragment on each call is rounded to 1 unit.

- USA charging rate does not include both Hawaii and Alaska.

- Using NT 001 from any fixed-line telephone, customer will receive the separate service invoice issued by NT.

- Using NTT 001 from any mobile phone networks, the service charge amount either will be included in the monthly telephone bill of the mobile postpaid customer, or will be deducted from a refill card of the mobile prepaid customer/mobile refill system.


International call to domestic Toll-free number is not free of charge. For example, BNO that begins with 800, 866, 877, or 888 in the USA are USA domestic Toll-Free and are free of charge for domestic calls in the USA only. If the call is made from a foreign country, the caller will be responsible for the international direct dial (IDD) service charge. To make a call, dial the IDD prefix followed by country code and the domestic Toll-free number, in this case, 001 1(for the USA) 800xxxxxxx or 009 1(for the USA) 800xxxx. The caller will be charged for IDD at 001 or 009 rates.

Another example would be when activating an HSBC credit card via a call center. Number +18663896638 is available free of charge only when the call is originated in the USA. If the call is made from Thailand with 001 prefixes, by dialing 00118663896638 the caller will be charged for IDD at 001 rates.

Call Collect or International Call Collect

To make call




Registration for volume discount

International telephone customers using NT 001 and NT 009 via any fixed-line telephone networks are welcome to register for combining invoice statements (Group bill) with NT. The group bill application is for a highly used customer to get the special volume discounts at 5 – 10% regarding the monthly service charge

  • No limit in terms of the amount of fixed-line telephone numbers to be collected for a group bill.

  • Combined group bill facilitates the receiving process of monthly bill.

  • No registration fee and no monthly fee.

  • The service charge has not been included in the value-added tax (VAT).

  • Group bill volume discount is applied for the use of NT 001 and NT 009 from domestic fixed-line telephone in Thailand, excluding, mobile phone numbers, Link numbers, and NT business fixed line numbers. 

  • The service balance date appeared in the bill is started on the first day and is ended on the last day of each month. Balance of the current month cannot be added to the following month.

  • The discount is only applied to the monthly service balance from the telephone numbers under the same Billing Account ID.

From August 2015 on, users of NT 001 and NT 009 who have a balance of less than 50 Baht per month will not receive the printed bill for that month. However, the bill will be sent whenever either the balance has been collected up to 50 Baht or the service duration reaches 3 months. (It depends on which condition comes first.)


There are some business contact numbers inside the United States with their information that to make a phone call from other foreign countries are Call Collect, for example, 1-605-335-2222 which is a contact number of Citi Bank credit card company in the US. If anyone makes a phone call with NT 001 from Thailand by dialing digits 00116053352222, he or she will be charged with NT 001 rate for the international phone call.

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