Basics
SIM + eSIM, Dual SIM, eSIM only: what phone spec sheets mean
What “SIM + eSIM”, “Dual nano-SIM”, “eSIM only” and “Dual eSIM” mean on a phone spec sheet, how many numbers fit, and which setup works best for travel.
“SIM + eSIM” on a phone spec sheet means a tray for one physical nano-SIM plus a built-in electronic SIM, so the phone can run two numbers at once. “Dual nano-SIM” means two slots for plastic cards, “eSIM only” means there’s no tray at all, and “Dual eSIM” means two eSIMs can be active at the same time. For travel, the most convenient phone is one where your home number and a travel eSIM fit side by side.
What SIM and eSIM setups do phones come with?
A modern smartphone stores numbers in one of five ways, and each has its pros and cons on the road. The same model can ship in different versions depending on the country, so always check the specs for the exact version you’re buying, not the model in general.
| Setup | Numbers at once | Pros for travel | Cons for travel |
|---|---|---|---|
| nano-SIM + eSIM | Two: one physical, one electronic | Home SIM stays in the tray, travel eSIM goes on as a second line | To use a local physical SIM, you have to take your home SIM out |
| Dual nano-SIM | Two physical | You can pop a local physical SIM in next to your home SIM | No eSIM chip, so no travel eSIM |
| Dual nano-SIM + eSIM | Usually two of three, depends on the model | Flexible: plastic and eSIM both work | Firmware decides which lines combine, so check your version |
| eSIM only | Two electronic, if Dual eSIM is supported | Travel eSIM installs with no tray fiddling | Your home number must be moved to an eSIM first; no local physical SIM |
| Dual eSIM | Two active eSIMs | Home number and travel eSIM are both electronic | Only works if your carrier has issued you an eSIM |
Dual eSIM isn’t a separate kind of hardware, it’s a capability. The iPhone 13 series and later support it, for example, as do many recent Android phones. A phone can have both a tray and Dual eSIM, in which case the spec sheet says something like “nano-SIM + eSIM, supports two eSIMs”.
What is Dual SIM Dual Standby (DSDS)?
Dual SIM Dual Standby, or DSDS, is a mode where both lines on a phone stay on standby and can receive calls and texts, but mobile data runs through only one chosen line at a time. Most two-number phones work this way, including “SIM + eSIM” and “Dual eSIM” models.
In practice, DSDS means that abroad you set the travel eSIM as your mobile data line while your home number stays reachable for calls and texts. What happens during a call on one line (whether the other line still takes calls or keeps data going) depends on the model, the carrier and VoLTE support, so check your phone’s specs for the details.
Why is SIM + eSIM the best setup for travel?
A “SIM + eSIM” phone is great for travel because your home number doesn’t have to move anywhere: the plastic card stays in the tray and the travel eSIM takes the second spot. Calls and bank texts keep coming to your home number, while mobile data runs through the eSIM on a local network.
- At home, on Wi-Fi, install the travel eSIM by scanning its QR code.
- Turn off mobile data on your home SIM so your data doesn’t go through your home carrier. Keep the line itself on for calls and bank texts; that requires roaming to be available with your carrier.
- Set the eSIM as your mobile data line and turn on data roaming for it: most travel eSIMs run on the local network as roaming, and without it you won’t get data.
- When you land, the phone registers on a local network and data starts flowing through the eSIM.
MoreSim works exactly like this: the eSIM goes on as a second line, your home SIM stays in the phone, and the plan starts counting on first connection in your destination. MoreSim plans are data-only, with no phone number: you call over messaging apps where the country doesn’t restrict them, and bank texts arrive on your home SIM.
What to check when buying a phone with SIM and eSIM
When buying an eSIM phone, check the specs for your country’s version, whether it has an EID, and whether it’s carrier-locked. Storage size or 5G in a product title (“512 GB eSIM phone”, “5G eSIM smartphone”) tells you nothing about how the phone stores numbers.
- Country version. The same model can come with or without a tray, and with or without eSIM, depending on the market. Look up the specs of the exact version on sale.
- The exact SIM wording. “nano-SIM + eSIM”, “2 nano-SIM”, “2 nano-SIM + eSIM” and “eSIM only” are different phones, and a bare “Dual SIM” guarantees nothing.
- EID. If dialing *#06# shows an EID, the phone has an eSIM chip. Ask the seller to check it in front of you.
- Carrier lock. Phones bought on contract abroad may be locked to a local carrier, and another SIM or eSIM simply won’t work in them.
- Support from your carrier. If the phone is eSIM only, confirm in advance that your carrier issues eSIMs and how to move your number.
Can you buy an eSIM like a regular SIM card?
You can’t buy an eSIM as a plastic card: an eSIM is a carrier profile that downloads onto a chip built into your phone, via a QR code or an app. When people search “buy SIM eSIM”, they usually mean either a phone with eSIM support or the profile itself from a carrier or a travel eSIM seller.
If a phone has no eSIM chip, you can’t install an eSIM profile on it directly. There are adapters, plastic cards that an eSIM profile gets written to, but they have their own compatibility and convenience limits; we cover them in the article on phones without eSIM.
Are 5G and eSIM related?
5G and eSIM are independent phone features: 5G describes a generation of mobile network, eSIM is a way to store a carrier profile. There are 5G phones without eSIM and vice versa. Whether 5G works on a particular eSIM depends on the phone, the network in the country you’re visiting and the plan’s terms; we go into detail in the article on eSIM and 5G.
FAQ
What does SIM + eSIM mean on a phone?
“SIM + eSIM” means the phone has a tray for one physical nano-SIM plus a built-in eSIM chip. It can run two numbers at once: one on the plastic card, one on the eSIM. For travel this is the easiest setup, because your home SIM stays in the tray and a travel eSIM goes on as a second line.
What is Dual nano-SIM + eSIM?
It’s a phone with a tray for two physical nano-SIMs and an eSIM chip on top. Usually only two of the three lines can be active at the same time, and which combinations are allowed depends on the model and firmware. Check the spec sheet for the version sold in your country.
Can I buy an eSIM like a regular SIM card?
No. An eSIM isn’t a card, it’s a carrier profile that downloads onto a chip built into your phone, via a QR code or an app. What you buy is the profile itself, from a mobile carrier or a travel eSIM seller. If your phone has no eSIM chip, there’s no plastic “eSIM card” to slot in; only adapters exist, and they come with their own limitations.
What’s the difference between Dual SIM and SIM + eSIM?
Dual SIM is the umbrella term for any phone that holds two numbers, while “SIM + eSIM” is one specific way of doing it: one physical card and one electronic profile. In store listings, “Dual SIM” often means two physical nano-SIMs. Look for the exact wording: “2 nano-SIM”, “nano-SIM + eSIM” or “Dual eSIM”.
Can I use an eSIM-only phone with my current number?
Yes, as long as your carrier issues eSIMs. Your carrier moves the number from the plastic card to an eSIM, so ask them about the process before you buy. A travel eSIM then goes on as a second line, provided the phone supports two active eSIMs.
Are 5G and eSIM related?
No, 5G and eSIM are independent features. 5G is a generation of mobile network, and eSIM is a way to store a carrier profile. There are 5G phones without eSIM and eSIM phones without 5G, and whether 5G works on a particular eSIM depends on the phone, the network and the plan.