If you're researching eSIMs while getting ready for a trip or studying abroad, you've probably hit the same worries a lot of people do: "Are there any downsides?" "Will I run into trouble later?" Here's the short answer: there are only a handful of things to watch out for with an eSIM, and most of them can be avoided simply by checking one detail before you buy or by understanding how it works. In this article, we'll honestly lay out the points that trip up first-timers and anyone who hasn't used their phone abroad in a while, along with how to handle each one. By the end, you should have a clear sense of whether an eSIM is right for you and what to prepare.
- The 5 main things to watch out for with an eSIM
- How to check device compatibility in 30 seconds
- How calls and texts actually work
- How to ease worries about deleting, setup, and data limits
- How to tell whether an eSIM suits you
What are the main downsides of an eSIM?
Let's start with the bottom line. There are roughly five things worth knowing about before you use an eSIM. Nearly all of them can be resolved by checking a detail before you buy or by understanding how things work. Rather than carrying around vague worries, it's faster to go through them one at a time.
| Point to watch | What it means | How to handle it |
|---|---|---|
| You need a compatible device | Requires an eSIM-capable phone that isn't carrier-locked | Confirm with a 30-second self-check |
| Data-only | No voice calls or SMS tied to a phone number | Use app-based calling / keep a number by other means |
| A bit of setup | Setup is needed before you leave | Done in a few minutes with a QR code or guide |
| Be careful about deleting it | Removing it may require re-downloading | Generally don't delete it / contact support |
| Connection quality varies | Depends on the local network, area, and congestion | Check supported networks and user feedback beforehand |
Point 1: You need an eSIM-compatible device
The bottom line: most recent smartphones support eSIM, so there's usually no need to worry too much. To use an eSIM, your phone needs to support the technology and must not be locked to a single carrier. The good news is that most major models from the past few years are compatible, and many phones sold in recent years ship carrier-unlocked. In a lot of cases, people already meet the requirements and are simply left with lingering doubts.
To get a sense of whether your phone is compatible, you can check for an EID number: go to "Settings → General → About" (iPhone), or dial "*#06#" in the phone app (many Android devices). The EID is the number used to identify an eSIM, and if it appears, there's a good chance your device supports eSIM. That said, final compatibility depends on the model and when it was purchased, so it's worth checking your device manufacturer's information as well. For step-by-step instructions, see how to check eSIM device compatibility.
Point 2: It's data-only (how calls and texts work)
This is where a lot of confusion comes up, so let's be precise. The Bloomy eSIM is data-only. You can't make or receive voice calls or SMS messages tied to a phone number. On the other hand, app-based calls that use data — like WhatsApp, Messenger, FaceTime, and similar apps — work as usual. In other words, it's not that "no calls work at all"; the only things you can't use are phone-number voice calls and SMS. Keeping that distinction in mind makes the whole thing feel a lot simpler. You can keep talking to family and friends right in the apps you already use.
If you need to receive SMS verification codes on a specific phone number — for banking, social accounts, and the like — consider keeping that number active or setting up an alternative verification method as a backup. Reviewing how your most-used services handle verification before you travel can save you a scramble on the day.
Point 3: A little setup (but it's done in minutes)
The bottom line: if you follow the QR code or the on-screen prompts, setup takes just a few minutes. In most cases, the safest approach is to install it over Wi-Fi before you leave and then activate the line once you arrive. If you install it ahead of time, getting started on location feels as simple as flipping a switch. Activation timing varies by plan, so check the guidance before you buy. Even if you're not used to this kind of setup, walking through the steps once beforehand makes it easy to stay calm and follow along. You'll find the full walkthrough in our setup guide.
Point 4: Deleting it can be hard to undo
As a rule, there's no need to delete an eSIM. It's perfectly fine to leave it on your phone after your plan ends, and deleting it by mistake may mean you have to download it again. So it's best to just leave it in place until you're done using it. Unlike a physical SIM, there's no card to "pull out," so before you delete one in the name of tidying up, it's worth pausing to confirm you really want to remove it. And if something doesn't work, start with our connection troubleshooting or reach out to support.
Point 5: Connection quality depends on local conditions
Speed and stability vary with the local network, the area you're in, and congestion at busy times of day. The same is true of physical SIMs — this isn't a weakness unique to eSIMs. In the suburbs, mountainous areas, underground, or at crowded venues, you may find the connection harder to come by. Checking the supported networks and user feedback for your destination before you buy can reduce surprises on the day. If you're concerned, leaving yourself a little extra data gives you room to stay calm in spots where Wi-Fi is hard to come by. Please note that real-world connection quality always depends on the local network, your device, and the specific area.
How to choose an eSIM: deciding on data, days, and country
Alongside the points above, one thing people often agonize over before buying is "how much data should I get?" Data needs vary a lot depending on how you use your phone, so it's easier to choose by starting from a benchmark close to your own habits. The table below is a general guide only. If you watch a lot of video or use tethering often, choosing one tier up gives you peace of mind.
| Example usage | Rough daily estimate | Who it suits |
|---|---|---|
| Mostly maps, messaging, and quick searches | About 0.3–0.5GB | Sightseeing, short trips |
| Social media, photo sharing, occasional video | About 0.5–1GB | Typical trips and business travel |
| Lots of video, video calls, and tethering | About 1–2GB or more | Studying abroad, long stays, remote work |
Because data needs vary by usage and region, treat the figures above as a rough reference at the time of checking. For the number of days, adding a little cushion to your length of stay helps you avoid trouble while traveling on your departure and return days. You can search plans for your destination by country, data amount, and number of days on our eSIM comparison page.
How eSIMs differ from physical SIMs and pocket Wi-Fi
With an eSIM, there's no card to insert or remove, so there's nothing to lose and nothing to forget to swap. Because you can add a data line for your destination without removing your existing SIM, you're also less likely to forget to switch back to your original SIM afterward. Each option has its strengths and weaknesses, so here's a quick summary.
| Option | Strengths | Things to watch |
|---|---|---|
| eSIM | No card, set up before you go, travel light | Needs a compatible device, data-only |
| Physical SIM | Works even on older phones | Swapping, loss, and pickup hassle |
| Pocket Wi-Fi | Easy to share across people and devices | Needs carrying, charging, pickup and return |
If you want to travel light on your own, an eSIM is a good fit; if you want a group to share one device, pocket Wi-Fi may suit you better. Choosing based on group size and how you'll use it makes it harder to go wrong.
Who eSIMs suit — and who they don't
eSIMs are a great fit if you rely mainly on data, want to handle setup before you leave, and prefer to keep your luggage and paperwork light. If you have a compatible device and mostly stay in touch through apps like WhatsApp, you're well placed to make the most of how easy an eSIM is. On the other hand, if you absolutely need voice calls or SMS tied to a phone number while you're away, or if your device doesn't support eSIM, an eSIM on its own won't be enough — it's better to consider it alongside a way to keep a number or another option. Figuring out which side you fall on in advance helps you avoid that "this wasn't what I expected" feeling after buying.
A pre-purchase checklist so first-timers don't get caught out
Finally, here's a quick rundown of what to confirm before you buy. Cover these before you leave and you'll be able to start using your eSIM with confidence once you arrive.
- Whether your device supports eSIM (check for the EID)
- Whether it's free of any carrier lock
- Whether you need phone-number voice calls or SMS (prepare a backup if so)
- Whether the data amount and number of days match your stay and usage
- Whether you've reviewed the flow of installing before you leave and activating on arrival
If you run into trouble
If you can't connect, check things in order: line activation, your mobile data settings, and whether data roaming is turned on. You'll find detailed steps in our connection troubleshooting, and answers to common questions in the FAQ. You can search plans for your destination by country, data amount, and number of days on our eSIM comparison page. If you'd like to learn more about the basics, our eSIM guide is a good place to start.
Please note: an eSIM is a data-only service with no phone number, SMS, or voice calling, and a fair usage policy applies. The information in this article is current as of June 2026. Supported devices and terms may change, and pricing should be confirmed at the time of purchase, so please check the latest details before you buy.
