Using Australian Samsung S6 Edge Overseas

Hi Guys,

Just looking for a bit of help. Hubby and I recently just got back from an overseas trip, which included a visit to both Vietnam and Thailand. We both bought local sim cards and had them installed and set up correctly by local residents.

One of us has an Iphone 5s which had no issues getting 3G or possibly even 4G in some places. The Australian Samsung S6 Edge (bought from JB HiFi) though was never able to pick up a 3G signal, I was always stuck on the H or H+ signal depending where I was, which was dreadfully slow. This applied in Vietnam and Thailand.

So I understand that different countries broadcast their networks on different frequencies, is there anything I can do to the phone itself to make it pick up an Asian 3g or 4G signal?

Not really just asking out of curiosity, as we might be moving to Thailand for an extended period of time, and so would love to have a phone that actually works over there! Really frustrating having a brilliant phone, but then not being able to use it to its potential over there.

Any help? Or has anyone else experienced similar issues?

Thanks!