Phones and SIM Cards -

Phones & SIM Cards – A Guide for Travellers to Southeast Asia

Let’s face it, not only are we more connected than we ever have been before but we are constantly craving more of that connection. The need to pull your phone out of your pocket and browse social media for two minutes while your partner is in the bathroom is all too real.

Should I Get a Local SIM Card for Each Country During My Travels in Southeast Asia?

Getting a local sim card for each country you visit is the best way to stay connected while travelling in Southeast Asia. WiFi is an option in some areas but it can be unreliable or downright slow. Having a local SIM card will give you access to travel apps like maps, hostel booking services and of course, the all-powerful Google!

Should I Get an International SIM Card for Southeast Asia?

International SIM cards are a good idea in theory. But in reality, they’re more expensive than local SIMs and don’t offer as much coverage across Southeast Asia. Having one as a backup is a good idea but for general use, a local SIM is the best option.

Best SIM Cards in Southeast Asia: Quick Answers!

To find out more about the mobile carriers in each country in Southeast Asia, click on the links below! 

Important information

Disclaimer – As with all things in Southeast Asia, prices, bundles and offers change frequently and some are only available in person. At South East Asia Backpacker, we are only a small team, so if you spot anything that needs updating, jump over to our community page and let us know!

Some countries have more networks than we have mentioned but often, these are not very good for travellers. We have chosen to omit them from these lists for several reasons. Sometimes it is because the coverage is hyper localised and only covers a few major cities or the providers do not have an extensive 3G/4G network. Some carriers only provide 2G coverage, which is great for locals wanting to stay in contact with their friends and families but no good for the internet-driven backpacker.

Some companies only sell sims to locals due to certain laws preventing them from selling to anyone else. They will quickly tell you this if you end up trying to buy the wrong SIM though so don’t let that put you off trying to find the best deals!

Before we take a deep dive into the actual SIM cards available across Southeast Asia, there are a few snippets of information and technical jargon that you should know. This will help you steer clear of bad deals and make the most of staying connected while travelling!

SIM card for iPhone
SIM cards come in different sizes, although it is possible to cut them down.

Different bandwidths 

Different carriers will use different bands (4G) or frequencies (3G) to provide their customers with a signal. What does that actually mean for you? And how do you know which bands or frequencies your phone can receive?

I don’t want to bore you to death with a crapload of technical mumbo-jumbo about cell networks and how they work, so instead, I will tell you what you need to know and cut out the rest. If you are interested, however, Whistle Out has a great intro to this topic (although it is very USA centric) which will leave you with a solid understanding of the technology we all use every day.  

The long and short of it is that some phones cannot connect to certain bands or frequencies. In the UK and Europe, this isn’t really an issue because most networks run on very similar systems and almost every phone can connect to them all. In Southeast Asia and the Americas, however, this is something that we have to think about. 

As you read through the SIM card information on this site, you’ll notice that we have included the bands or frequencies that each carrier uses. If you already know which bands your phone uses, then this information will prove useful but if like me, you don’t have a clue, then check out Will My Phone Work. This simple site has data for almost every phone and every carrier in the world. Select your phone make and model, destination country and network of choice from the drop-down menus and it will quickly tell you whether or not your phone will work.

There are also totally different types of mobile phone networks such as CDMA and GSM but, to be honest, that’s a real rabbit hole to dive down and you would be better served getting accurate information about those from a professional within the technology world. 

To keep it simple, unless you are from the USA and even then only using certain networks (Sprint, Horizon, US Cellular), your phone will be automatically set up to use the GSM system. This is ubiquitous in almost every country across the globe, so unless you purchased your phone from one of the aforementioned carriers, it will already be set up to work in most countries. 


At home, we are all used to seeing the little 4G symbol in the corner of our phone screens but what does this actually mean and is it the same in Southeast Asia? 4G is the fourth generation of mobile phone network technology with 3G being the third and 2G being the second. Each one is exponentially better than the previous generation with 5G promising to offer speeds of up to 1gbps!

Just to complicate things a little, you may be used to seeing an LTE symbol in place of the 4G. LTE or Long Term Evolution, in simple terms, is a massive upgrade from the 3G systems but not quite as good as real 4G should be. It is a sort of middle ground between 3G and 4G but 3.5G just doesn’t have a good ring to it.

Various networks across Southeast Asia support 2G/3G/4G and LTE but the coverage varies and they do not all support all network types. For each company mentioned, we have also noted which network types they use. If you know you will be predominantly be using the SIM for data, avoid the networks that only provide you with 2G and 3G.

Can I use any SIM in my phone?

Unlocked phones

Most smartphones today are not cheap and the average price is only going up. The best way to offset this cost is to get a contract through any of the carriers available in your country and pay the phone off over a period of years. It’s a great way to stay up to date with the latest tech but it does leave you tied into using that carrier for the period of the contract.

A way for the networks to do this is to “lock” the phone to their network, meaning it cannot be used with another provider’s SIM. In most cases it is a simple task to get your phone unlocked, simply contact the carrier and explain that you would like to unlock the phone. If you have finished paying off the contract, then they will do this without issue or at least, they should. If you haven’t finished paying off the phone, it can be more challenging and even if they agree, you will still have to pay for the contract that you are no longer using plus there is often an admin fee involved.

The fee’s change between networks but aren’t likely to be more than $20 USD. Once unlocked, the phone will work with any SIM from any network so, providing the phone is capable of receiving the correct bands and frequencies, it will work with local SIMs while travelling. If you buy your phone outright from the manufacturer, then it will come unlocked and you are already set!

Different Types of SIM

SIM Sizes

There are three different sizes of SIM card available, (four if you count an eSIM but we’ll get onto that below) these are; Standard, Micro and Nano. Most modern smartphones will use one of the latter two sizes but in many parts of the world, it can be hard to find the exact SIM to fit your phone.

In most Southeast Asian countries, you’ll find all SIM sizes but there is always a chance that the particular vendor you choose will have run out. To save you messing around to finding another place to buy a sim, it’s handy to know that you can actually cut any standard SIM down to fit your phone.

YouTube video


The latest phones from Apple, Samsung and Huawei, as well as a few other brands, come with a built-in eSIM as well as the traditional SIM card slot. This is great for travellers because it means you can upload your normal “at home” number and SIM information onto the eSIM. Once this has been done, you have the SIM card slot totally free to use for any local sims you pick up on your travels, without risking losing your normal SIM card in the bottom of your bag! 

With both the eSIM and a regular SIM activated in your phone, you can switch effortlessly between which number you want to use, depending on your requirements and location.  At the moment, not all phones or carriers support eSIMs but do check if it is possible for yours to do so.

The information is freely available on phone manufacturer and network provider websites. Having an eSIM really is a massive help when trying to stay connected on the road. 

Dual SIM Phones

Dual-SIM phones do exactly what they say on the tin. They are phones with the ability to hold and use two SIM cards at the same time.  Almost every smartphone manufacturer sells Dual SIM models of their flagship phones but they do not come this way as standard and therefore, not many people tend to have them. They used to be solely the domain of high profile business execs who wanted to keep their business and private lines separate but did not want to carry two phones with them. 

These days, eSIM enabled phones are taking over the market once dominated by Dual SIM phones but that does not mean they don’t still have their uses. If you have a Dual SIM phone then you should utilise this whilst travelling, so you can keep both your regular SIM and a local SIM ready to go at all times. 

There are also some countries where it is recommended to have two local SIMs if you will be travelling around a lot. This is because some carriers provide an amazing connection in one part of the country but next to no signal in other parts. Having two SIMs can help you stay connected, no matter where you are in the country, giving you one less thing to worry about.

Tourist SIMs

Almost every major carrier across Southeast Asia offers tourist specific SIM cards. These are tailor-made for travellers and often come with large data allowances but way fewer minutes or texts. Some actually offer “data only” sims, which can be great value for those only wanting data. If you are staying in a country for just a short time, a few weeks or less, then these sims generally offer the best value for money but be warned, this is not always the case.

It is also worth noting that tourist sims usually expire after a set period. Sometimes you can keep them active by topping up before the expiry date but there are a few providers who will not allow this. Make sure you look for this information before making a purchase. You really don’t want your SIM giving up on you whilst you are using Google Maps to hunt for your next hostel! 

Tourist SIMs are usually available in official stores, from street vendors and are often for sale in the arrivals area of most Southeast Asian airports.

International SIM Cards

International SIM cards are big business in this day and age, with many companies vying for your hard-earned money. Until recently, these SIMs were very expensive and not always reliable but as the demand and competition have grown, so has the quality of the product and thankfully, the price is coming down. 

That is not to say that international SIM cards are the best choice for you. For many backpackers, they are still more expensive than picking up a local SIM but they do hold some advantages.  There is often a language barrier when trying to buy a local sim.

In some instances, the person selling you a SIM will speak English or at least have English instructions on hand but this is not always the case. Having an international SIM already set up with an app set to your own language can take a lot of the stress out of getting that all-important internet connection sorted out.

With an international SIM already set up and ready to go, you don’t have to hunt around for a local SIM as soon as you arrive in a new country. It means you can book an Uber, load Google Maps or use any number of great travel apps as soon as you arrive! 

Many international sims come with data packages that allow the use of certain apps, such as Facebook, Instagram, WhatsApp or Youtube, without eating into your data allowance. It is also common to see local sims advertising this but with that aforementioned language barrier, it’s often tricky to set these up correctly. 

The downside of international sims is still the overall cost. They do tend to be more expensive but if you are hopping between a lot of countries in a relatively short amount of time then the cost of buying a new SIM in each country also adds up quick. 

If you like the idea of having an international SIM for convenience, then consider doubling up and using local sims as well if you will be in a country for more than a week. This is where having a Dual SIM phone would really come in handy! You will still save money and have internet access wherever and whenever you need it. 

Pad Thai stall in Bangkok
It can be hard to know where you can buy SIM cards in Southeast Asia. 

Getting Online 

Bundles and Packages

Often when buying a sim, you will also need to choose a bundle or package to make it cost-effective. Most companies provide different packages depending on what you need them for so have a good look at your options before you make a purchase.  It is worth pointing out that if you do not purchase a bundle, you will tear through your balance very quickly! To maximise your credit, turn your data off before you top up. If you top up without doing this, your phone will automatically start using data and start costing you money.

Once you have chosen your package, turn the data back on and providing you have picked a bundle with a data allowance, everything will work as it should.  I made the mistake of not doing this on my last trip and had only topped up the exact amount I needed to purchase the package I wanted. By the time I went to buy it, my phone had automatically used a good portion of my credit on refreshing apps and emails so I had to return to the shop to buy more!

Official Stores

In many countries across the world, you can buy SIM cards from official stores or smaller shops that are not affiliated with the main carrier. Whilst it is often more convenient to just go to the first shop you see, it can often be beneficial to go a little out of your way and head to the official, branded store. 

You will often find better deals and bundles, as well as a higher level of customer service. In most large cities, the official store will have at least one employee who can speak English and will help you choose the best SIM card and bundles for your needs. 

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