The best replacement for viber is whatsapp.

The best alternatives to viber are rated as following:
★★★★★  whatsapp
★★★★★  skype
★★★★  line
★★★  tango
★★  facetime
★★  kik
★★  talkatone
★★  viber out
★★  rebtel
★  kakao
★  imessage
★  hangouts
★  telegram
★  truphone
★  pinger
★  vonage
  line app
  voxer
  skype data usage
  line better
  nimbuzz
  skype iphone
  google talk
  google voice
  bbm
  wechat

Your alternative for viber is not listed? Suggest!
Speaking about viber, one probably shouldn't forget about video call.

Other search terms related to viber and their ratings are:
★★★★★ video call
★★ free call
number
You have in mind a companion for viber and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of viber in all years. Click on graph for more.
viber
whatsapp
skype