Originally Posted by yowflyer
If you bought your cell phone in Canada, it is most probably "locked" so you won't be able to insert a SIM card while travelling.
When you get to HK, make sure you buy a tri-band or quad-band GSM phone so you can use it when you get back to Canada. In Hong Kong, it is not necessary to buy the phone from a network operator - you should get a better deal at some of the other dealers.
HK pay as you go SIM cards are quite inexpensive. My HK SIM card is from the network operator called "3". It was HK$98 and you get the SIM card plus over 300 minutes of airtime for that amount. You can use this SIM card to roam but it may be a bit expensive.
In Thailand, I bought a SIM card for 200 baht (US$5), which will include enough airtime for a couple of days depending on how much you use it.
In Singapore, you can get a SIM card for about S$8 (US$5) which will include S$10 in airtime. Each minute will cost about S$0.20-0.22 depending on the carrier.
I haven't been to the Phillipines yet. They don't use GSM phones in South Korea.
Thank you very much yowflyer, that's great info. I really don't need a phone that I can use back here as I have a mobile phone through TELUS, which probably is much cheaper then using a phone I bought in HK.
Once you buy a SIM card in Thailand or Singapore, can you top that SIM card up or do you just buy a new one each time?
Does each SIM card come with their own phone number?
Philippines does use SIM cards too. To bad about S. Korea.