Traveling is fun! But paying for international roaming sucks and setting up an eSIM blows. I just want my US phone number to work normally without the $12 per day charge! No lie, this is a complex thing to figure out for yourself. Lucky you – that’s why I wrote this article! You”re’ll be digging into settings you should never have to see and clicking things you won’t fully understand. Buckle up… it will be worth it. Here’s a summary of what worked for us.
Disclaimer: This is for AT&T Customers with an iPhone.
If you’re an AT&T customer traveling abroad for more than a short vacation (2+ weeks), using AT&T’s International Day Pass can get expensive quickly. At $12 (2026) per day of use, a 30-day stay could cost up to $360, while a travel eSIM such as Saily can provide mobile data for a fraction of that cost.
With the right iPhone settings, you can use the inexpensive eSIM for your internet connection while keeping your regular U.S. AT&T phone number active for calls and texts through Wi-Fi Calling. This guide walks through the settings needed to minimize the risk of triggering AT&T international roaming charges while still using your phone normally abroad.
So here’s the special sauce… AT&T allows you to make calls through WiFi – bypassing their network altogether. This means they can’t charge you a roaming fee! I know… whaaaat?? It’s like, you have WhatsApp powers using your US carrier but they keep that on the down low. As long as you have WiFi, you can get free international calls as long as these specific settings set.
First Hurdle – Pay the Piper
Your phone must be unlocked to accept an eSIM. However, your iPhone MUST be fully paid off to be unlocked. And if you’ve been with AT&T long enough, you’ll know that you probably owe them a good chunk of change for those “trade-ins” which seem to amount to simply buying a new phone. So pay it off, then get it unlocked here: https://www.att.com/deviceunlock/.
Get an eSIM
This is not sponsored content. Our research showed Saily (https://saily.com/) to be one of the better options for an eSIM. Saily is a travel eSIM service that lets you purchase an international mobile data plan without replacing your existing AT&T SIM or changing your U.S. phone number.
After installing a Saily eSIM on a compatible iPhone, you can keep both your AT&T line and Saily active at the same time: Saily provides the inexpensive internet connection, while your AT&T line remains associated with your regular U.S. number. With Wi-Fi Calling enabled, a compatible iPhone may also use the Saily data connection to carry calls and texts for your AT&T line, helping you stay reachable without relying on AT&T’s normal cellular roaming service.
You can view available countries and data plans on the Saily website or download the app from the Apple App Store. Once the eSIM is installed and activated, the following iPhone settings will help ensure Saily is used for mobile data while minimizing the risk of triggering AT&T international roaming charges.
iPhone Settings Checklist
- Cellular → Cellular Data → [Saily]
- Cellular → Allow Cellular Data Switching → [Off]
- Cellular → Default Voice Line → [Primary / AT&T]
AT&T / Primary line
- Cellular → SIMs → Primary → Turn On This Line → [On]
- Cellular → SIMs → Primary → Wi-Fi Calling → Wi-Fi Calling on This iPhone → [On]
- Cellular → SIMs → Primary → Voice & Data → [LTE]
- Cellular → SIMs → Primary → Voice & Data → VoLTE → [On]
- Cellular → SIMs → Primary → Data Roaming → [Off]
- Cellular → SIMs → Primary → Network Selection → Automatic → [On]
Saily eSIM
- Cellular → SIMs → Saily → Turn On This Line → [On]
- Cellular → SIMs → Saily → Data Roaming → [On]
Other settings
- Cellular → Wi-Fi Assist → [Off]
- Apps → Default Apps → Calling → [Cellular]
- Wi-Fi → Wi-Fi → [On]
In Conclusion…
For AT&T customers traveling internationally, especially those planning an extended stay abroad, combining an international travel eSIM like Saily with AT&T Wi-Fi Calling can be a much more affordable alternative to paying daily International Day Pass fees.
By setting Saily as your iPhone’s cellular data provider while keeping your AT&T number active for Wi-Fi Calling, you may be able to receive calls and texts on your U.S. phone number while using low-cost international mobile data.
Before traveling, always confirm your current AT&T international roaming policy and rates, since carrier terms can change, and test Wi-Fi Calling before leaving the United States. With the correct iPhone dual-SIM and eSIM settings, long-term travelers can significantly reduce international phone costs while staying connected to their existing U.S. phone number.