What Is an eSIM, and Does Your Phone Support One?

Last checked: Nov 2026 · Updated November 4, 2026 · 9 min read · By the Signal Atlas research desk

If you have ever stood in an airport queue to buy a local SIM card, an eSIM is the shortcut you were missing. This guide explains what an eSIM actually is, what a "travel eSIM" adds on top, and — most importantly — how to confirm your own phone can use one before you pay for a plan.

What an eSIM is

A SIM's job is to tell a mobile network who you are and which plan you are paying for. For decades that information lived on a small plastic card. An eSIM ("embedded SIM") moves it onto a chip that is permanently built into the phone. Instead of swapping plastic, you download a small profile — usually by scanning a QR code, tapping a link, or pressing a button inside an app.

Apple describes the eSIM as an industry-standard digital SIM built into iPhone, and notes that an iPhone can hold eight or more eSIMs, although only a limited number can be active at the same time. In practice that means you can keep your home line on your phone and add a separate travel data plan next to it.

What a "travel eSIM" is

Companies such as Airalo, Nomad, Saily, Holafly, Ubigi, Maya and Yesim sell prepaid data plans that you install as an eSIM. Most of them are not mobile networks themselves. They buy capacity from network operators in each country and resell it to travelers as short-term packages. A few practical consequences follow from that:

• Most plans are data-only. You typically get mobile internet but no local phone number. Calls and messages go through apps like WhatsApp, FaceTime or Signal. Some providers sell add-ons — for example, Saily advertises an optional US number with a call-and-text plan, and Nomad's help center says only its Thailand, UK and Maldives plans include calls and texts.
• Your phone "roams" on a local network. That is why setup instructions almost always tell you to turn on data roaming for the travel eSIM line. Doing so on the travel line does not trigger your home carrier's roaming charges — those apply to your home line, which you can leave switched off for data.
• Plans are measured in data and days. A plan ends when you use up the data or when the validity period runs out, whichever comes first.
• "Unlimited" often has a daily fair-use cap. For example, Saily's Japan unlimited plan gives 5 GB per day at full speed and then 1 Mbps for the rest of the day, and Nomad states that speed drops to 1 Mbps after the daily high-speed allowance on its unlimited plans. Read the plan details, not just the headline.

How to check whether your phone supports eSIM

Compatibility is the single most common reason a travel eSIM purchase goes wrong, so it is worth five minutes. Work through these checks in order.

Step 1: Check the model

iPhone: Apple's support page says you need an iPhone XS, iPhone XS Max, iPhone XR or later. Google Pixel: Google's Pixel help says Pixel 3a and later can use one physical SIM plus one eSIM, and Pixel 7 or later can run two eSIM profiles at once if the carrier allows it. Samsung and other Android brands: support varies by model and by the country the phone was sold in, so check the manufacturer's own specification page for your exact model number.

Step 2: Look in Settings

• iPhone: open Settings → Cellular (or Mobile Data). If you see Add eSIM or Add Cellular Plan, the hardware supports eSIM.
• Pixel: open Settings → Network & internet → SIMs. An option to add a SIM and "set up an eSIM" means you are good to go.
• Other Android: look under Connections or Network for "SIM manager" or "Add eSIM". Menu names differ between brands.

Step 3: Find your EID (optional but definitive)

Every eSIM-capable phone has a 32-digit EID. On most phones you can see it by dialing *#06# or in Settings → General → About (iPhone) / About phone (Android). If an EID appears, your phone has an eSIM chip.

Carrier locks and regional models

Two things can block an eSIM even on a compatible model:

1. Carrier lock. If you bought your phone on a contract, it may be locked to your carrier. A locked phone may refuse another company's eSIM. Ask your carrier to unlock it before you travel; you usually cannot do this from abroad in a hurry.
2. Regional hardware. Apple's page notes that in mainland China only certain recent models (it lists iPhone 18 Pro, iPhone 18 Pro Max, iPhone Duo, iPhone 17e and iPhone Air) support eSIM, and that some Hong Kong and Macao models use two physical nano-SIM slots instead. If you bought your phone in one of those markets, check carefully.

What an eSIM won't do

• It won't make coverage appear where networks don't reach. Rural areas, mountains and ferries can still be patchy — several providers say so on their own pages.
• It won't usually give you a local number for bank or ride-hailing SMS codes. Keep your home line installed (with roaming data off) so you can still receive texts if your home carrier allows it.
• It isn't always transferable. Holafly, for example, says its eSIM can't be reinstalled once installed, so deleting it by accident means buying a new one. Don't delete a travel eSIM until the trip is over.

Next steps

Once you've confirmed your phone is compatible and unlocked, read our step-by-step installation guide, then compare providers in our four-way comparison. If you want to try the process with no risk, see our roundup of free and low-cost eSIM trials.