Alex Ruben
How To Fix Internet Switching to Other SIM During Calls on Dual SIM Android Devices
So, if you’re tired of your Android phone flipping between SIMs for data whenever you’re on a call, you’re not alone. It’s pretty annoying, especially when you’re trying to game or binge a video. The cause? Usually, the default settings or carrier restrictions that make the phone switch to a different SIM’s data during calls. Here’s what kind of weird workaround can fix that mess.
Step 1: Check if your SIMs support VoLTE
This one’s pretty much the foundation. VoLTE (Voice over LTE) lets your phone keep using 4G for calls—so no more yanking the data connection during calls. If VoLTE isn’t enabled, your device might be defaulting to 3G or even 2G for voice, leading to switching issues. To check:
- Go to Settings.
- Tap on Connections or sometimes Network & Internet.
- Navigate to Mobile Networks.
- Look for VoLTE or Enhanced LTE Mode and switch it on.
If you don’t see VoLTE options, might be a carrier support thing or your SIM isn’t compatible. Sometimes, enabling Wi-Fi Calling can help too.
Step 2: Choose your Data SIM and set it to LTE/4G
This step helps your phone stick to one SIM for data, especially if the system is trying to switch around. In Mobile Networks, pick the SIM you want to use as your main data source. Set it to LTE or 4G—fairly straightforward. On some phones, you get a toggle called Preferred Data SIM.
Pro tip: make sure your SIM supports 4G LTE — some older or cheaper ones don’t. This helps prevent the phone from reverting to 3G/2G during calls.
Step 3: Enable data on both SIMs during calls
This one’s a bit of a trick because not all devices have this toggle, but if you see Allow All SIMs to Use Data or similar, turn it on. Basically, it tells the phone not to restrict data to a specific SIM while you’re on a call. Usually found in Mobile Data or SIM settings.
Why it helps? Because your device doesn’t have to shift data roles mid-call, which caused the switch in the first place. Might not work on every device, but it’s worth trying.
Step 4: Disable auto data switching
This setting, found in Settings > Connections > SIM Card Manager or sometimes under Mobile Data, can be the culprit. If your device has a toggle called Auto Switch, turn it off. This prevents the system from automatically deciding which SIM to prioritize for data, keeping things stable.
On some setups, you might need to go deeper—like via hidden menus or through ADB commands if the toggle isn’t visible. Because of course, Android has to make it harder than necessary.
Method 2: Set your primary data and call SIMs explicitly
If your phone allows it, set your preferred data SIM as primary for calls too, in Settings > Calls or similar. Some devices let you pick which SIM to use as default for voice, which can stop the switching if the phone defaults to a different one for calls or data.
Been on some setups where this just straight-up fixes the problem. Not sure why it works, but on one phone, switching the primary call line to the same as the data SIM just stabilized everything.
Method 3: Restart and reset network settings (a classic)
After fiddling around, a restart often clears weird glitches. If that doesn’t help, go for Settings > General Management > Reset > Reset Network Settings. Be warned—that resets Wi-Fi passwords and Bluetooth pairings, but it doesn’t wipe data.
Sometimes, a fresh start on network configs just does the trick. On one device, it took a restart, then re-enabling VoLTE, and suddenly, no more switching. Weird, but useful.
Extra tips & common issues
If none of this sticks, check with your carrier — they sometimes have restrictions or specific configs that override your device settings. Also, keep your OS updated, because Android updates can tweak how dual SIM or VoLTE work. On some, those updates either clear up the bug or make it worse.
Conclusion
Fixing auto-switching of mobile data during calls isn’t super hard once the right options are enabled and set. These steps kinda help avoid the data flickering or disconnecting mid-call. It’s a mix of enabling VoLTE, setting your preferred SIMs, and turning off auto switch modes that make a difference, at least on most devices.
Frequently Asked Questions
What is VoLTE and why is it important?
VoLTE = voice over LTE; it keeps your calls on 4G so Internet stays active during calls. Without it, calls often fall back to 3G or 2G, causing the device to switch data roles or drop data altogether. Pretty essential for dual SIM users wanting stable connectivity.
What if my SIM doesn’t support VoLTE?
Answer’s usually: contact your carrier about upgrading your SIM or device. Some carriers disable VoLTE for certain plans or regions, so double-check if they support it first.
Will resetting network settings delete my stuff?
Nope, just your Wi-Fi passwords, Bluetooth pairings, and mobile data settings — so no worries about losing personal info.
Summary
- Enable VoLTE if available
- Set your main data SIM to LTE/4G
- Allow all SIMs to use data during calls if option exists
- Disable auto data switching if you find it
- Restart afterwards — sometimes that’s all it takes
Hopefully this shaves off a few hours for someone. Sometimes, it’s just about configuration. Good luck!