Viber says ‘To call someone using this service, go to any contact in Viber and tap any of the numbers listed next to Viber Out.’

Here is the list of supported destinations:

Landline and mobile (all numbers):

• USA & Canada
  
• UK
  
• Australia
  
• China
  
• Hong Kong
  
• India
  
• Indonesia
  
• Italy
  
• Japan
  
• Korea
  
• Malaysia
  
• Singapore
  
• Thailand

Landline only (no mobile numbers):

• Argentina
  
• Brazil
  
• Croatia
  
• Cyprus
  
• Denmark
  
• France
  
• Germany
  
• Greece
  
• Hungary
  
• Ireland
  
• Israel
  
• Lithuania
  
• Luxembourg
  
• Malta
  
• Mexico
  
• Netherlands
  
• New Zealand
  
• Norway
  
• Peru
  
• Poland
  
• Portugal
  
• Romania
  
• Russia
  
• Spain
  
• Sweden
  
• Switzerland
  
• Venezuela