You are about to buy an eSIM for your trip and you spot the words "data-only" next to the plan. It sounds like it might be missing something important, and you are not sure if that means no calls, no texts, or something else entirely. Here is exactly what it means, in plain terms.
Quick answer: a data-only eSIM gives you internet access abroad but no traditional calling or SMS number of its own. You can still make calls and send messages using apps like WhatsApp, since those run over the internet, and your regular Jio, Airtel or Vi SIM keeps handling your actual phone number for calls and OTPs.
What data-only actually means
A data-only eSIM connects your phone to a mobile network abroad so you can use the internet, but it does not come with a phone number you can be called on directly, and it cannot send or receive traditional SMS text messages.
Think of it as buying pure internet access for your phone, the same way your home wifi router gives you internet without a phone number attached to it. Most travel eSIMs, including the ones most people buy for a holiday, are data-only, because most travellers only need internet, not a new local phone number.
Can you still make calls on a data-only eSIM?
Yes, but through apps rather than the traditional way. WhatsApp calls, video calls, and voice notes all use your data connection instead of a phone network, so they work perfectly well on a data-only eSIM.
This covers almost everything most travellers actually need: calling family back home over WhatsApp, messaging your hotel through an app, or booking a Grab or Uber ride, which all run on data. What a data-only eSIM cannot do is receive a traditional phone call or SMS on a new number, the kind your bank might use to send a one-time code.
This is why keeping your Indian SIM active still matters
Since a data-only eSIM has no calling number, your Jio, Airtel or Vi SIM is still the one that keeps your actual Indian phone number reachable. Most phones that support eSIM can run your Indian SIM and a data-only travel eSIM together, in what is called dual SIM mode.
This means your Indian number stays live for GPay and PhonePe OTPs, bank alerts, and any calls from home, while your data-only eSIM handles the actual internet use abroad. We cover this setup in detail in our guide on receiving OTPs while using a travel eSIM abroad.
Data-only eSIM vs a full plan with calls and SMS
| Question | Data-only eSIM | Full plan with calls and SMS |
|---|---|---|
| Gives you internet access | Yes | Yes |
| Comes with a new phone number | No | Yes, a local number in that country |
| Can receive a traditional SMS OTP on it | No | Yes, on the new local number |
| Works for WhatsApp calls and messages | Yes | Yes |
| Suits most short holiday trips | Yes, for most travellers | Better if you need a local number for local businesses |
Who actually needs calls and SMS included, not just data
A data-only eSIM covers most holidaymakers and business travellers completely. You would only need a plan with an actual local number if you are dealing with a local landlord, applying for something locally, or need a local business to call you back on a number in that country.
For a short trip to Thailand, Dubai or Europe, most Indian travellers find that data-only, combined with WhatsApp and their Indian SIM kept active, covers everything they need without any gaps.
Setting up a data-only eSIM correctly before you fly
Install your data-only eSIM while you still have wifi or your Indian SIM's data, ideally the night before your flight out of any Indian airport. Our eSIM installation guide covers the exact steps for iPhone and Android.
Once installed, set the data-only eSIM as your line for data, and leave your Indian SIM switched on for calls and SMS. You can check whether your exact phone model supports this setup on the eSIM compatible device list.
A data-only eSIM covers almost everything a modern trip actually needs, from Google Maps to WhatsApp calls home. Browse data eSIM plans by destination on Olysim's plans page before you fly.
