This was first explained to me by a friend who got a new Sun Cellular SIM. Then, last week I got to talk to a marketing manager from Sun who lent me a phone with their new Sun Cellular International SIM in it and adds that their international SMS is only Php1.
I asked her if there was some special gateway or SMS-over-IP sort of thing that allowed them to offer international SMS rates this low (it’s usually Php15/SMS). She said there’s none and just attributes it to hardwork of their bizdev team to partner with telcos from other countries.
Commercial Name:Â Call & Text International Sim
Pre-loaded with Free 5 minutes of IDD 10* (valid for 30 days)
– Free 5 iSMS to 20 destinations** per month for 6 months (1st month is free; for the 2nd-6th month, subs must load at least Php50 worth of load to avail the free 5 iSMS)
Special Rates: Php1 per iSMS to 20 destinations**
– $0.20/min IDD rate to 20 countries***
Price of SIM pack: Php49

It’s not really applicable to all countries though. For the calls and SMS, they mostly target regions where there are a significant number of OFWs living.
This is almost similar to Globe’s OFW SIM although that one comes with paired SIM cards (one is for local and the other is roaming-ready). The OFW market, with over 8 million Filipinos working abroad, remains to be an open battleground for such telco services and we’ve yet to see any dominant player in that segment.
* IDD 10 countries: US Main, Canada, China, HK, Singapore, Thailand, Malaysia, Guam, Macau & Brunei.
** iSMS 20 destinations: USA, Canada, Singapore, Hong Kong, United Arab Emirates, Malaysia, Macau, Japan, Qatar, Brunei, Guam, Hawaii, Oman, Cayman Island, Cyprus, Turkey, Northern Marianas Island, Jamaica, Bahamas & Puerto Rico.
*** IDD 20 countries: Saudi Arabia, United Arab Emirates, India, Japan, Australia, South Korea, Taiwan, Italy,Indonesia, Hawaii, Kuwait, Bahrain, Germany, Spain, Israel, France, Greece, Jordan, Northern Marianas Islands & Cyprus.


How to register isms 20?.. thanks… :D