"I want cheaper data when I travel or stay somewhere for a while — but I don't want to give up my current phone number or my SMS verification codes." If that sounds like you, the approach worth knowing is the dual SIM setup: keep your phone number on your current SIM and handle data with a separate eSIM. In short, on a compatible phone you can run a voice SIM (calls and SMS) and a data-only eSIM on a single device at the same time. This isn't a "switch" that changes your number — it's an "add-on" that splits the roles, so no one's number is lost. This article walks through how it works, the benefits, the things to watch for, device requirements, the setup flow, and some practical examples — in plain language.
- You can keep your number as-is and simply add data with an eSIM
- A data-only eSIM has no number, SMS, or voice calls — but app calls (WhatsApp, etc.) work fine
- Receive SMS verification codes and calls on your existing voice SIM to keep your number active
- You must confirm your device supports dual SIM (physical SIM + eSIM, or eSIM + eSIM)
- For the voice side, a low-cost prepaid plan can be cheapest, while a flat-rate plan is the most hands-off and worry-free
First, check whether your phone supports two lines on the eSIM compatible devices page. If you'd like to browse plans, taking a look at the eSIM plan comparison page first will make the rest of this guide easier to picture.
What is dual SIM? Splitting the roles between voice SIM and data eSIM
Dual SIM is a setup that lets a single phone hold two lines at the same time. The basic idea is simple: "calls and SMS stay on your current number (voice SIM)" and "data goes on a separate eSIM." Your number stays exactly as it is, so your family and work contacts, SMS verification, and all your account registrations keep working.
Two ways to combine your SIMs
The SIM formats available depend on your device. The two common combinations are:
- Physical SIM + eSIM: keep your current number on the physical SIM, and add an eSIM for data.
- eSIM + eSIM: some phones (for example, iPhone 13 and later) can use two eSIMs at once.
Which one you can use depends on the model. It's a good idea to confirm "dual SIM / eSIM support" on the compatible devices page beforehand.
Benefits of a dual SIM setup
Because you can switch only your data while keeping your number, this helps in situations like these:
- Travel and business trips: cover data at your destination with an eSIM, while still being able to receive SMS verification and calls on your usual number.
- Study abroad and long stays: buy just the local data you need on an eSIM, and keep your home number.
- Extended stays in another country: keep your home number active while getting affordable local data through an eSIM.
- Trimming your everyday phone bill: let an inexpensive voice plan handle calls and SMS, and use a data-efficient eSIM for data — splitting the two can lower your monthly cost in some cases.
Things to watch for and downsides (let's be upfront)
It's convenient, but there are points worth knowing before you sign up.
An eSIM is generally data-only
Many data-only eSIMs, including Bloomy, do not support a phone number, SMS, or voice calls. That's exactly why the dual SIM idea is to keep "number and SMS on the voice SIM" and "data on the eSIM." If you need SMS verification, you'll receive those codes on your SMS-capable voice SIM. Note that app-based calls (such as WhatsApp) still work over data on the eSIM.
Your device must support dual SIM
To run two lines at once you need a compatible device. Older models or certain carrier-lock situations may not work, so checking the compatible devices page is essential.
"Unlimited" plans come with conditions
Large-capacity and unlimited-style plans suit heavy or long sessions, but fair usage policies, speed management after a certain amount of use, and whether tethering is allowed can vary by plan, network, and local congestion. "Unlimited" does not mean "completely without any limits," so it's wise to check the latest conditions before buying. We've laid out how to think about unlimited on the unlimited eSIM page.
How to choose the voice plan that keeps your number (a neutral overview)
For the "calls and SMS" side, people generally pick an affordable voice plan that's well suited to keeping a number alive. Pricing and conditions differ by carrier and country, and prices are quoted in USD where shown — always confirm the current price at the time of purchase. There's no single right answer; the choice depends on whether you want the lowest cost or hands-off peace of mind.
| Voice plan type | Data | What it's good for |
|---|---|---|
| Pay-as-you-go / prepaid voice plan | Add as needed | Among the cheapest ways to keep a number. SMS usually supported. Watch out: many prepaid lines expire if you don't top up or use them within a set period, so they need a little ongoing attention. |
| Low flat-rate plan with a small data allowance | Small monthly allowance | A set-and-forget option — the number stays active automatically for a small monthly fee. Less risk of accidental expiry. |
| Minimal "calls & SMS only" plan | Little or very slow data | For people who use the line purely for calls and SMS verification. Browsing may be impractical on this kind of plan. |
| Entry plan from a major carrier | Small allowance | Often the most stable network. Check the latest price on the carrier's official site. |
Roughly speaking: if you want the absolute lowest cost, a prepaid plan that needs a little upkeep; if you want it hands-off, a low flat-rate plan. Prices and conditions change, so always confirm the latest details on each carrier's official site.
Choosing an eSIM for your travel or local data
For the data side, choose your eSIM based on your destination (or usage area), the data volume you need, and how many days you'll use it. The advantage is buying only what you need — a few GB for a short trip, or a larger allowance if you watch a lot of video or tether often. With Bloomy you can search plans by country, data volume, and number of days. If you're unsure how much data you'll need, start by comparing day-and-volume combinations on the comparison page.
The setup flow (how to set your default lines)
Once you're used to it, the dual SIM setup takes just a few minutes. The basic flow is:
- Confirm your device is compatible (compatible devices page).
- Sign up for and activate your voice SIM (the number side).
- Add the data eSIM and install it via QR code or similar.
- In your device settings, split the roles: "default voice line = voice SIM" and "mobile data = eSIM."
- While traveling, turn off data on the voice SIM to avoid unintended charges.
You'll find the step-by-step install instructions in the setup guide. If you can't get connected, see what to do when it won't connect.
How much difference can splitting your plan make? (with assumptions noted)
By "keeping your number on your current carrier and moving only data to an eSIM," some people can lower their monthly bill. The example below assumes you're comparing against a typical mid-tier postpaid plan with a moderate data bucket (without promotional discounts). Your result depends on your current contract and how much you use, so treat this as a rough illustration rather than a promise.
| Setup | Number (voice SIM) | Data (eSIM) | Rough monthly idea |
|---|---|---|---|
| Lowest cost | Prepaid voice plan with minimal upkeep | eSIM sized to your needs | Among the lowest, but needs a little attention |
| Hands-off and worry-free | Low flat-rate voice plan | eSIM sized to your needs | Slightly higher, set-and-forget |
| Calls & verification only | Minimal calls & SMS plan | Smaller eSIM allowance | Lowest data usage |
As you can see, simply rethinking how you hold your data — without changing your number — can make a difference. That said, we can't claim it will always halve your bill. If you choose a prepaid voice plan, factor in the risk that the line could expire if you forget to top it up in time. Prices, data allowances, and terms can change, and amounts shown are in USD where applicable — always confirm the latest details with each provider.
What you can do with Bloomy
Bloomy is a data-only eSIM. It doesn't come with a phone number, SMS, or voice calls — but with a dual SIM setup, your number stays right where it is. You can choose plans by country, data volume, and number of days, so on the comparison page you can find one that fits your destination and how you'll use it. After purchase, check your remaining data and QR code in My Account, and if setup gets confusing, the setup guide has you covered. Please note that connection quality varies with the local network, your device, and the area you're in. For anyone who thinks "I don't want to change my number, but I'd like my data to be lighter and more flexible," it's an easy option to lean on.
