Even though I have been living in Thailand for almost 2 years now, somehow I still managed to keep my old Mentari GSM (Indonesian based pre-paid card) mobile number active by using its International Roaming (IR) feature. Nonetheless, I don't use this GSM card to make and receive call in Thailand because it will be very costly, instead I just keep it on stand by. It's just that I like this GSM number so much I decided to keep it and whenever I go back home for holidays, my friends can still call me at my old number.
What I like about this GSM card is that you can receive SMS/Text message for free, while other providers will charge you around Rp 3500-5000 per SMS received abroad. If you send SMS/text message to Indonesia while abroad, Mentari will charge you Rp 3500/SMS, but this is still cheaper than making or receiving a call.
According to Mentari CS, this IR feature is automatically on as long as we have a minimum balance of Rp 75,000. Please contact the Mentari CS before you go to check which GSM providers in the destination country that we can connect to.
On arrival, if you cannot automatically connect to the host network, you need to manually select it from your mobile phone. Go to the Setting menu > Network selection > Manual selection. In Thailand, you can choose either DTAC, AIS or TH GSM.
To check your balance, type : *101# then OK or *555# then OK
To top up your balance, type : *102*[voucher code]# then OK or *556*[voucher code]# then OK
For more detail, go to Klub Mentari website here.
Note : early this year, I still use *102* to top up my balance but few days ago tried again but it failed, then I tried *556* and it worked.