Let me talk about sim cards...
- There is NO global or even multi-country wireless provider. Each country's laws about foreign ownership and how wireless infrastructure works prevents that. As an example, Virgin Mobile is based in the United Kingdom but you've also seen the Virgin brand in America and Canada and so you think that your UK Virgin sim can work in America. WRONG. Actually it's local carriers that either partnered with Virgin UK or they have the rights to use the Virgin brand. Either way, you're actually using the local carriers.
- Hong Kong's 3 network allows you to use their prepaid sims in a small handful of other Asian countries. All that means is that 3 has a roaming agreement with carriers in Thailand, Philippines or whatever country it is. With a 3 sim you're not using 3 in Thailand, you're roaming on the DTAC (or whatever company) network. Roaming charges apply.
- As per above, whichever wireless carrier you're with, when you go traveling and use the same sim, you'll just be roaming on a local carrier's network and paying the roaming charges as per your home carrier's agreement. The reason people recommend travelers buying a local sim when traveling is because roaming charges are often 10x more expensive than your regular at home local charges.
- Tri- and qua-band phones are often recommended because the GSM infrastructure is widespread around the world, allowing you to roam on that country's wireless carriers. Quad-band phones were unique maybe 5 years ago, but since chipsets have gone down in price pretty much every phone is tri- or quad-band. CDMA was a former competing protocol against GSM but carriers in major countries are on the way to converting both CDMA and GSM to LTE. There is also the AWS/1700 protocol which is used by some wireless carriers. If you have an AWS phone then you're screwed. You'll need to buy a new phone to use in other places. | |
