eSIM vs Physical SIM

Nearly every phone sold in Singapore now supports both an eSIM and a physical SIM, so you have to decide which format to activate and rely on. The claims you will find are contradictory. Some pages say eSIMs have weaker signal. Others say they drain your battery, or that they lock you to a single telco.

The wrong choice has a cost. A physical SIM means waiting for delivery, and ordering a replacement if you lose it. An eSIM installed without checking your handset first can leave you without a working line when you arrive. Apple has already removed the tray from some models, so the question will come up again on your next phone.

This guide covers how each type works, where they actually differ, which suits how you use your phone, and which of those claims hold up. Every claim below is checked against manufacturer and industry sources rather than repeated from another blog. By the end you will know which format suits your phone and the way you travel.

What Is an eSIM?

An eSIM (embedded SIM) is a small chip soldered onto your phone's motherboard during manufacturing. Instead of the chip itself carrying your identity, your telco sends a profile, a package of encrypted credentials, over the internet, and that profile is what tells the network who you are.

The proper technical name for the hardware is an eUICC (embedded Universal Integrated Circuit Card). The rules governing how profiles get downloaded onto it are set by the GSMA, the global industry body for mobile operators, under a specification called SGP.22. Every eSIM on every compliant phone worldwide follows the same standard.

How Does an eSIM Work?

Only the first two steps need anything from you. Steps three to five are handled automatically by your phone and your telco. The sequence looks like this:

You buy a plan. Your telco generates a profile for your line and puts it on a server (a subscription manager, in the jargon).
You get an activation trigger. This is usually a QR code, an in-app "install" button, or a manual activation code plus server address. giga offers all three on its eSIM plans page.
Your phone fetches the profile. The software on your phone that handles this is called the Local Profile Assistant. It checks the server's certificate against the GSMA's own certificate authority, so a rogue server cannot hand your phone a fake profile.
A secure channel opens. The chip and the server authenticate each other using a challenge-response exchange, and the profile is downloaded encrypted end to end.
The profile activates. Your phone registers on the network and the line goes live.

The whole thing usually takes a couple of minutes. You do need to be online for step 3, which is why every telco tells you to sit on Wi-Fi while you do it.

What Is a Physical SIM?

A physical SIM is the removable card you already know: a plastic chip you slide into a tray. Every physical SIM contains the same core information as an eSIM profile. The difference is packaging. Your credentials are written onto the card at the factory and stay on that card for its whole life.

Physical SIMs have shrunk over the years, from the credit-card-sized originals down through mini, micro, and now nano, which is the size in essentially every phone sold in Singapore today. Nano SIMs are roughly 12.3mm by 8.8mm and are mostly chip with a sliver of plastic around the edge.

How Does a Physical SIM Work?

Slot it in, and the metal contacts on the card meet pins in the tray. Your phone reads the card, pulls the identity and keys off it, and registers on the network. There is no download step and no need for internet access, which is the one genuine advantage of the format: a physical SIM works the second it touches the pins, even with no data connection anywhere.

To switch phones, you take the card out of one and put it in the other. To switch telcos, you get a new card. Both actions are entirely in your hands, and both require you to physically have the card.

eSIM vs Physical SIM: Key Differences

Form: an eSIM is a chip soldered into the phone. A physical SIM is a removable nano card.
How you get it: an eSIM downloads over the internet, usually in minutes. A physical SIM is collected in person or delivered.
Setup needs: an eSIM needs Wi-Fi or mobile data. A physical SIM needs a SIM ejector pin and no internet at all.
Moving to a new phone: an eSIM transfers wirelessly, or you reinstall it from a QR code or your telco's app. A physical SIM you move across by hand.
Multiple lines: one eSIM chip holds several profiles, switched in Settings. A physical SIM gives you one line per slot.
Losing or damaging it: an eSIM cannot be lost or damaged, because it is part of the phone. A physical SIM can be bent, scratched or simply misplaced.
Theft: an eSIM cannot be pulled out of your phone. A physical SIM can.
Signal and speed: identical on both, because they use the same modem and antenna.
Device support: eSIM works on most phones from roughly 2018 onward, though you should check yours. A physical SIM works on almost anything, including older and budget handsets.

That last point is worth a closer look. eSIM and physical SIM are two ways of storing credentials. Neither touches the radio hardware. Your speed and coverage are determined by the network, your location, and your phone's antenna.

eSIM Pros and Cons

eSIM Pros

You get connected almost immediately. Sign up, install, done, with no trip to a shop and no waiting on delivery. If you have ever been stuck without a working line on a Sunday evening, this alone sells it.
It cannot be lost, bent, or damaged, so it never needs replacing. The chip is soldered to the board, so there is nothing to scratch or bend. There is no replacement card to order and no replacement fee to pay, because there is nothing to replace.
You can hold several lines on one phone. Keep a work number and a personal number, or a local line and a travel line, and switch between them in Settings. Many recent phones let two profiles stay active at once.
It resists SIM-swap theft better.
No plastic. Every eSIM is one less card, one less carrier packet, and one less courier trip.
It survives the cold better than a card does. Testing has found physical SIM contacts can lose a little stability in freezing conditions as the metal contracts, where a soldered chip stays put. In Singapore this is a non-issue. On a ski trip, less so.

eSIM Cons

You need internet to install it. This is the catch travellers hit. Land in a new country with no roaming and no Wi-Fi, and you cannot download a local profile. The fix is to install before you fly.
Not every phone has one. Older handsets, many budget models, and plenty of secondhand phones are physical-SIM only. Cheap backup phones especially.
Moving your line to a new phone takes a few more steps. Modern transfer tools have made this quick, but it is still more involved than moving a card between two trays. If your old phone is dead or wiped, you may need to reinstall from your telco's app rather than transfer directly.
You cannot simply hand your line to someone else. Passing a friend your SIM card so they can use your data for an afternoon takes seconds. Moving an eSIM means transferring or reinstalling the profile.

Physical SIM Pros and Cons

Physical SIM Pros

It works on virtually anything. Old phones, hand-me-downs, cheap travel handsets, that Nokia in the drawer. If it takes a nano SIM, it works.
No internet needed to set up.
Moving it takes ten seconds. Pin, tray, card, tray, done. No app, no account, no QR code.
You can hold it. For some people that matters, and it is a fair preference rather than a technical argument.

Physical SIM Cons

It is a small object, and small objects go missing. They are easiest to lose during a swap, when the card is out of the phone. Replacing one means contacting your telco and waiting for a new card to arrive.
Getting one takes time. Collection or delivery, either way you wait.
It is removable, which is the whole problem with SIM-swap fraud. Someone with your phone for two minutes has your number.
One card, one line. Want a second number? You need a second slot, and many phones only have one.

Which Should I Choose, eSIM or Physical SIM?

Choose an eSIM if your phone supports it and any of this sounds like you:

You want your line to be live today.
You travel and want a local data profile without hunting for a shop at the airport.
You want a work line and a personal line on one handset.
You have already lost one SIM card and would rather not repeat the experience.

Stay on a physical SIM if any of this sounds like you:

Your phone has no eSIM support.
You often move your line between handsets, such as a spare phone for the gym or a work phone at weekends.
You regularly need to activate a line with no internet nearby.

For most people in Singapore with a phone bought in the last few years, eSIM is the better default. Coverage is identical, setup is faster, and there is nothing to lose or damage. Switching is reversible, so it is a low-stakes thing to try. If you want to make the move, giga's step-by-step guide to switching to eSIM walks through the automatic, QR code, and manual routes on both iOS and Android.

Why Choose giga?

Plenty of telcos will tell you their eSIM is great. Here is what giga can point at instead of adjectives.

Rated 4.7 stars across more than 25,000 Google reviews. Not a stat pulled from a survey giga commissioned. Real customers, publicly, at a volume that is hard to game.
4.5 stars on both the App Store and Google Play, across roughly 9,000 ratings between them. For a telco whose entire service lives in an app, this is the number that counts: sign-up, plan changes, eSIM install and payment all happen there.
Powered by one of the most reliable networks in Singapore, per Opensignal. giga does not run its own testing and ask you to take its word for it. Opensignal measures real-world mobile experience from billions of readings taken on ordinary people's phones, and publishes its Singapore Mobile Network Experience Report publicly so you can check the results yourself.
Gino, the 24/7 chatbot, sorts out most things without a queue. Bill query at 2am, eSIM install stuck, roaming question the night before a flight. Gino handles the bulk of it on the spot, and passes on what genuinely needs a human.
The whole journey is digital, start to finish. Sign-up, plan choice, one-click eSIM activation in the app, payment, changes later. No shop, no forms, no hold music. giga is upfront that its plans are not built to win a race to the bottom on price. What it does obsess over is making every step of using it painless.

And the things that make the plan itself worth staying on, once the eSIM is installed: no contracts and no hidden fees, so leaving is always your call. Rollover data, so what you paid for does not evaporate at month end. Free roaming across Asia on every plan, extending to 48 destinations on 5G plans, which is the bit that matters if you picked an eSIM for travelling in the first place. Keep your existing number when you port in.

Have a look at giga's mobile plans, led by gigaFLEX+ and all eSIM-enabled, or at gigaRoam if the next thing on your calendar is a flight.

Hear From Our Satisfied Customers

“Purchased one of their SIM card via giga App, hassle free, chose my desired phone number as well. Door step delivery is available, just choose a date and time and boom! You have your physical SIM card OR you can opt for eSIM. It’s really your choice!”

- TWOWHEELS ENOUGH

“I really appreciated the free roaming feature while travelling in Asia, especially during my trip to Malaysia. It saved me the extra cost of activating a separate roaming plan and spared me the hassle of adjusting phone settings or swapping SIM cards. Everything worked smoothly the moment I landed. It made staying connected so much easier.”

- Neo Meng Keong

FAQs

Is it worth switching to eSIM?

If your phone supports it, yes for most people. You lose nothing (same network, same speeds, same number), and you gain instant activation, multiple lines on one device, and a line that cannot be lost or physically stolen. The main reason not to is if you regularly shuffle your line between handsets.

Which has better signal strength, eSIM or physical SIM?

Neither. Independent testing has found no meaningful difference in baseline signal between the two, because signal is a function of the network, the tower, your surroundings, and your phone's antenna. If your reception is poor, changing SIM format will not fix it.

Is eSIM more expensive than a physical SIM?

The plan is the same plan on the same network. Some telcos charge a small admin fee to swap an existing line from physical to eSIM, so check with yours before you switch.

Is eSIM available on all phones?

No. giga's compatibility list covers recent handsets from Apple, Samsung, Oppo, Xiaomi, Honor, and Huawei, and lists iPhone 11 and newer as supported. Check the eSIM page or your manufacturer's site for your exact model before you commit.

Can I have both eSIM and a physical SIM at the same time?

On most dual-SIM phones sold in Singapore, yes. That is the standard setup: one card in the tray, one profile on the chip, both active. Many recent iPhones (iPhone 13 and newer) can also run two eSIM profiles simultaneously and store additional ones.

Can I transfer my eSIM to a new phone?

Usually, and it has become much simpler. On iPhone, eSIM Quick Transfer moves a line from your old iPhone to your new one wirelessly if your carrier supports it, with both devices on iOS 16 or later. Android has its own equivalent: Pixel supports transfer from the Pixel 6 series on Android 13 and up, and Samsung added it in One UI 5.1, though some carriers still ask you to authenticate through their app partway through. Failing all that, you reinstall the profile from your telco's app or a fresh QR code.

Can I convert eSIM back to physical SIM?

Yes, assuming your phone still has a tray. Ask your telco for a physical SIM and they will issue one against your line. It is not a one-way door, though there may be an admin fee, and phones without a tray obviously cannot go back.

Do I keep the same number with an eSIM?

Yes. Swapping your existing line to eSIM keeps your number exactly as it is. Moving to a different telco keeps it too: mobile number portability in Singapore is regulated by the IMDA and works across telcos and MVNOs, prepaid or postpaid. Your new provider starts the port, not your old one, and it typically completes within a few hours to a business day.

Can I get 5G with an eSIM?

Yes. 5G depends on your phone's modem, your plan, and network coverage where you stand. The SIM format has nothing to do with it. All giga plans support 5G.

When will eSIMs replace physical SIM cards?

Gradually, and not on any published deadline. The signal to watch is Apple: the iPhone Air is eSIM-only worldwide, and the standard iPhone 17 line ships without a tray in twelve markets including the US, Japan, Canada, and much of the Gulf. Singapore's iPhone 17 models still have trays, as do those in Europe, Australia, and South Korea. Expect the list of eSIM-only markets to grow with each generation.