Calling Sao Tome and Principe from the United States explained:

• 011 - US exit code; dial first for international calls made from the USA or Canada
• 239 - Country Code for Sao Tome and Principe
• Phone Number - 7 digits
• US to Sao Tome and Principe landlines international dialing format: 011 239 22 ?????

How to dial to Sao Tome and Principe cellular:

• dialing format for calls to a cell phone: 011 239 99 ????? (or 98 ?????)

Phone Books:

• Servico Informativo 103 - Sao Tome et Principe phone book, in Portuguese

Updates:

• Sao Tome telephone numbering changes - January 2010