hike-to-hike calls are free on your phone.
Launch hike and Open the chat window with the person you wish to call. To start a hike-to-hike call:
Tap on the call button on the top action bar of the chat window.
Once the call is connected you can:
Tap to mute the call
Tap to put the call on hold.
Tap to turn the speaker on or off, or switch to a headset.
Tap to end the call.