Dual SIM Guide: Keep Your Home-Country Number and Save on Data with an eSIM

Want cheaper mobile data while traveling, but don't want to lose your current phone number or the SMS verification codes tied to it? A dual SIM setup can help. You keep your number on your current SIM and add a separate eSIM for data only. On a compatible phone, one device can run a voice SIM (calls and SMS) and a data-only eSIM at the same time. You're not switching providers or porting your number. Each line simply does a different job, so your number stays exactly where it is. This guide covers how it works, the benefits, the catches, device requirements, setup and how to work out whether it will save you money.

To check whether your phone supports two lines, see our eSIM-compatible devices page. If you're already looking at plans, our eSIM plan comparison page will make the rest of this guide easier to follow.

What Is Dual SIM? How a Voice SIM and a Data eSIM Share the Work

Dual SIM means having two active lines on one phone. The idea is simple: your current number (voice SIM) handles calls and SMS, and a separate eSIM handles data. Your number doesn't change, so family, work contacts, SMS verification and account sign-ins all keep working as before.

Ways to combine two SIMs

The supported SIM types depend on your device. The two most common setups are:

• Physical SIM + eSIM: keep your current number on the physical SIM and add an eSIM for data.
• eSIM + eSIM: some phones, including iPhone 13 and later models, can run two eSIMs at once.

Which setup works depends on your phone model. Before you buy, check on our compatible devices page that your phone supports dual SIM and eSIM.

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Benefits of a Dual SIM Setup

Because you can switch your data without touching your number, dual SIM is useful when you're:

• Traveling for vacation or business: an eSIM covers data at your destination, and you can still receive SMS codes and calls on your home-country number.
• Studying abroad or staying long term: buy only the local data you need on an eSIM and keep your home number active.
• Traveling often: keep one number for life and add a data eSIM for each country you visit.
• Trying to lower your everyday phone bill: a low-cost voice plan can cover calls and SMS while a data-efficient eSIM covers browsing, which may reduce your monthly costs.

For more ways to save on your phone bill, see our smartphone savings category.

Things to Know Before You Start

Dual SIM is convenient, but there are a few limits you should know about before you sign up.

Most eSIMs are data-only

Like many travel eSIMs, Bloomy is data-only and does not include a phone number, SMS or voice calls. That's why the setup splits the work, with your voice SIM handling the number and SMS and the eSIM handling data. SMS verification codes will arrive on your voice SIM, which has to support SMS. To learn more about phone numbers and SMS, browse our phone number and SMS category.

Your phone must support dual SIM

Running two lines at once requires a compatible phone. Older models and carrier-locked phones may not work, so check our compatible devices page first.

Unlimited plans come with conditions

High-data and unlimited plans suit heavy use, but fair use policies, speed reductions after a certain amount of use and hotspot availability vary by plan, network and local congestion. Unlimited does not mean there are no limits at all, so check the current terms before you buy. Our unlimited eSIM page explains how this works.

Choosing a Plan to Keep Your Number

For the calls-and-SMS side, most people choose a low-cost plan whose main purpose is to keep their number active. Your mobile carrier at home, or a budget brand that uses the same networks, may offer plans like these. Availability and pricing vary by country and provider, so the table below compares plan types, not specific prices. No single option is right for everyone. The main question is whether you care more about the lowest cost or the least hassle.

Plan type (examples)	Monthly cost	Data	Things to consider
Prepaid or pay-as-you-go	Very low. Check when you buy	Top up as needed	Often the cheapest way to keep a number, but many prepaid lines expire after a period without a top-up or activity. You'll need to track this. Check whether SMS is included.
Low-cost plan with a small data allowance	Low and fixed. Check when you buy	Around 1GB	Fixed monthly billing keeps your number active even if you forget about it. A good choice for peace of mind.
Talk-and-text-only or very low-speed plan	Low. Check when you buy	None, or very slow speeds	Barely usable for browsing. Best if you only need calls and SMS verification.
Your current carrier's smallest plan	Varies. Check when you buy	Small allowance	Usually a stable network and no number transfer. Compare the price against budget options.

In short, prepaid usually costs the least but takes occasional attention, while a fixed monthly plan takes no effort. Prices and terms can change, so check each provider's official site for the latest details.

Choosing a Data eSIM

Choose your data eSIM by destination (or coverage area), how much data you need and how many days you'll use it. A few GB is usually enough for a short trip. Choose a larger plan if you stream video or use your phone as a hotspot. With Bloomy, you can search plans by country, data amount and duration. If you're not sure how much data you need, start with our comparison page to compare combinations of days and data.

Setup Steps (and Choosing Your Default Lines)

Once you know the steps, setup takes a few minutes:

1. Check that your phone is compatible on our compatible devices page.
2. Sign up for and activate your voice SIM (the line with your number).
3. Add the data eSIM and install it, usually by scanning a QR code.
4. In your phone's settings, set default voice line = voice SIM and mobile data = eSIM.
5. When abroad, turn off mobile data on your voice SIM to avoid unexpected roaming charges.

For step-by-step installation instructions, see our setup guide. If you can't connect, try our troubleshooting page.

Will It Save You Money? A Simple Way to Check

Keeping your number on a low-cost plan and moving your data to an eSIM can lower some people's monthly costs. To check whether it works for you, compare these numbers:

Step	What to check
1. Current bill	What you pay each month now for calls, SMS and data
2. Number-keeping plan	The monthly cost of a low-cost voice plan that keeps your number
3. Data eSIM	The cost of a Bloomy plan that matches your data use. Check the current price when you buy
4. Compare	If step 2 plus step 3 comes to less than step 1, the split setup may save you money

Changing how you handle data while keeping your number can make a real difference. Savings aren't guaranteed, though. Results depend on your current plan and how much you use. If you choose a prepaid line, include the risk of it expiring if you forget to top up. Prices, data allowances and terms can change. Check each provider's official site for the latest details.

What Bloomy Offers

Bloomy is a data-only eSIM. It doesn't include a phone number, SMS or voice calls, but in a dual SIM setup your current number stays as it is. Plans are sorted by country, data amount and duration, so you can use our comparison page to find one that fits your trip. After you buy, My Account shows your remaining data and your QR code. If you get stuck, our setup guide walks you through each step. Connection speed and quality depend on the local network, your device and your location. Bloomy is a simple option if you want to keep your number but carry less baggage on your data.