Phone Numbers in Tristan da Cunha: Formats and Dialing Rules

Quick Reference Guide

• Country: Tristan da Cunha
• Country Code: +290
• International Prefix: 00
• National Prefix: None

Overview

This technical guide offers a comprehensive look at the telephone numbering system in Tristan da Cunha (TA). It is essential for telecom professionals, developers, and system administrators seeking detailed information on phone number structures, dialing procedures, and management in TA. The guide aligns with ITU-T recommendations and includes practical examples, regular expressions, and number portability insights.

Number Structure and Formats

General Number Structure

Due to Tristan da Cunha's small population and limited telecom infrastructure, phone numbers follow a straightforward structure. There are no area codes, and all numbers are 4 digits long.

• Country Code: +290
• Subscriber Number Length: 4 digits

Regular Expression for Number Validation

To validate a phone number in Tristan da Cunha, use the following regular expression:

/^\+290\d{4}$/

Number Formats by Type

Dialing Procedures

Domestic Calls

• Landline to Landline: Dial the 4-digit local number directly (e.g., 8234).
• Landline to Mobile: Dial the 4-digit local number directly (e.g., 8834).
• Mobile to Mobile: Dial the 4-digit local number directly (e.g., 8834).

International Calls

• Outgoing International Calls: Dial 00 followed by the country code and the destination number.
• Incoming International Calls: Dial +290 followed by the 4-digit local number.

Number Portability

Currently, Tristan da Cunha does not support number portability due to its small size and limited telecom infrastructure. All numbers are managed by a single operator.

Telecom Operators and Number Ranges

Major Telecom Operator

• Sure South Atlantic Ltd: The sole telecom operator in Tristan da Cunha, managing all number allocations under the +290 country code.

ITU-T Standards

Tristan da Cunha's numbering plan adheres to the following ITU-T standards:

• ITU-T E.164: Defines the international public telecommunication numbering plan.
• ITU-T E.123: Provides guidelines for the notation of telephone numbers.

Number Allocation and Management

Regulatory Body

Telecommunications in Tristan da Cunha are regulated by the Communications Regulator of St. Helena, Ascension, and Tristan da Cunha. This body oversees the allocation and management of phone numbers within the territory.

Number Allocation

All numbers in Tristan da Cunha are allocated by Sure South Atlantic Ltd under the supervision of the Communications Regulator. Given the small population, the numbering plan is straightforward with no need for complex allocations or area codes.

Technical Considerations

Special Cases

• Golden Numbers: There are no specific provisions for golden numbers due to the limited numbering plan.
• Number Blocking: Number blocking services are not typically available due to the small telecom market.

Developer Considerations

• Integration: Ensure systems support the +290 country code and recognize the 4-digit format.
• Validation: Use the provided regular expression to validate phone numbers from TA.
• Internationalization: Ensure systems handle both incoming and outgoing international calls, adhering to the outlined dialing procedures.