Calling Laos from the United States explained:

• 011 - US exit code; dial first for international calls made from the USA or Canada
• 856 - Country Code for Laos
• Phone Number (may not begin with 0):
  • fixed - 8 digits, area code included
  • cell phones - 10 digits
• sample call from US to a landline in Vientiane: 011 856 21 ??? ???

How to dial to Laos cellular:

• dialing format for calls to a cell phone: 011 856 20 ???? ????

Area Codes:

Phone Books:

• Tourism Laos - official website providing useful information, including links to local businesses and institutions

Updates:

• Laos telephone numbering changes - June 2010