Travellers Guide to Mobile Communication in Thailand
The process should work anywhere in the world – shhhhhh, don’t tell your mobile carrier service provider.

If you’re travelling, how to stay connected with the world is an important question to answer wherever you’re going. Yet it’s not really one of the things people give much thought to beforehand; they just get sucked into whatever costs their mobile carrier says , rather than looking for more affordable options. You either accept the international roaming charges from your carrier (which can really add up) or arrive at an airport and think, “I’d better get a local sim card.” The local sim card option then means you lose the benefits of having your “home” phone number.
These days however, the most important and powerful solution to this problem is generally in our own hand. Our phone itself. People often underestimate the power of what modern mobile phones are capable of. Sure, we have all these apps and they do all these smart things, but the smartest part of what our phones can do is behind the scenes. Full disclosure, for feature comparison I use an iPhone 12pro, while highly featured, there are many options from different manufacturers with the required feature set for reliable and cost-effective mobile communication solution while travelling in Thailand (and before you ask – yes, this solution should work just about anywhere in the world!)
Since I’m from Australia I’ll run through the options for the Australian mobile companies, then tell you the solution that works for me. It won’t be dissimilar for travellers from other countries.
In Australia we have Telstra, Optus and Vodafone. Both Telstra and Optus offer international roaming packs that cover calls and 1Gb of data for around $10 per day. Vodafone is $5 a day for the same service. On all of them, once you exceed the 1Gb data you get charged for basically another entire day. Use another 1Gb, get charged… again and again and again. Of course, this works out very well for the telco, though not for you. So, if you ask a telco in Australia about using your phone overseas, the only option they will give you is their international roaming.
On

On my latest trip to Thailand, I was planning on staying for 3 months, so international roaming (I’m with Telstra at home – the largest carrier) would end up costing, gulp, around $900. If I didn't go over the daily allowance. I have business at home and an elderly mother. I needed to be contactable with my “home” phone number, but surely there was a better way. Being a techy person and not minding research I started looking at how the system works and figuring out if I could come up with a better option.
Telstra was the first company to provide a service called “WIFI Calling”, however both the other carriers now also use this service. I’m sure the situation would be the same in countries with a similar level of communications technology. This services means that on a compatible device (which is any phone less than a few years old – you’ll have to check your specific handset), when the phone is connected to a WIFI hotspot, the calls and texts you make and receive are actually going through the WIFI, not the carrier’s phone tower down the street. Guess what: for my Telstra service, it doesn’t care where that WIFI is, as long as there is a data connection. Thailand is very well served with WIFI. Every hotel, most cafes, restaurants and bars, most any service providors, have WIFI – there’s even free WIFI around many towns. The result: if I’m on WIFI somewhere I get all the advantages of international roaming using WIFI Calling without any of the international roaming charges! Let’s hope that there’s no way the mobile carriers can plug that hole. I haven’t tested Optus and Vodafone for their WIFI Calling internationally but they use it at home and I’ll assume it’s going to operate much the same as Telstra.
So we know that we can make and receive calls and texts while we’re connected to WIFI, but what about when we’re out and about?
Firstly, to use WIFI Calling a phone only needs data access, it doesn’t care if it’s a WIFI hotspot or over

another network. But if you’ve got your existing SIM in your phone, needed for your “home” number to work, how do you get on another mobile network? Well, most phones these days have the ability to use a dual SIM. They are even more likely to be able to use an eSIM (an eSIM is like a built-in SIM card that can be programmed as you need it by scanning a QR code). Therefore, the solution to this part of the problem is straightforward.
I’ll assume that you’ve got a phone that’s eSIM capable. To get an eSIM prepaid service all you need to do is get online and purchase an eSIM. You’ll be sent an email with a QR code; scan the QR code, and voila! You have an additional service/line on your phone. It might take a little bit of messing with settings the first time around, but once you get the hang of it, like magic your phone is working as if it was on a WIFI hotspot. No international roaming charges while you’re out and about.
Given the time I spent trying to 1) understand the websites of the three local Thai carriers and b) trying sign up to one, I’ll just give you my solution for getting an eSIM.
I purchased mine from airhub. They provide data only esims for many countries. It cost about $25 AUD for 30Gb of data that lasts a month at 4g speed. When the data runs out it throttles down, so you get a full 30 days at least. Remember that all the places you regularly go will have wifi so your mobile data goes further. Fair warning: the phone number you get with the esim will possibly have a different country code. For Thailand mine was Hong Kong. Don’t panic. Forget using the number. It’s just for administration. These are data-only eSIMs. Finally, I’ll state the obvious: yes, if you’re in Thailand and call a local Thai phone it will be an international call as it'll be using your “home” number to make the call.
In Thailand, and many places however, nearly everyone uses messaging platforms like “WhatsApp” and in Thailand “Line” is the most common,

download these apps and use them if needed rather than making local calls – it’s probably safer to message a business than phone anyway so as not to risk interpretation or understanding issues. Also, most hotels these days will ask for your WhatsApp number. Obviously since you’re online all the non-carrier based messaging and social apps just work.
As you can see, we are no longer in the communication dark ages. The major telcos however won’t tell you all this as they want you to think you have to pay their exorbitant international roaming charges. The only other word of warning is that if someone from home calls or texts it may not always come up on your phone as their number. Sometimes it might show a different number from Australia, sometimes it might show a Thai number. I’ll live with that slight inconvenience. Oh, voicemail also works just fine, just like as if I was at home, without it being an international call.
There you have it. With just a little very basic messing around, the simplest and most affordable way of providing yourself with a reliable and cost-effective communication solution while travelling is already in your hand! All the service you have at home with the additional ability to be anywhere in the world, without it costing you an arm and most of a leg.