After doing some simple research, I’ve discovered Skype offers the cheapest way to call Philippine Mobiles from Japan at 33 yen/min.
- Brastel charges 43 yen/min.
- Softbank charges 72~130 yen/min.
- NTT charges 85 yen/min.
- AU charges 129~171 yen/min.
If you know of alternatives, do let me know. Right now, I use Skype when I’m home and Softbank otherwise.