Weak Phone Signal? What to Try, in Order: Isolating Device, Settings, Location, and Network

Suddenly, the signal got bad.

The bars are full, but pages won’t load. Or it says no service.

“Is the carrier down?” you think. Yeah, you do.

But sometimes you can fix it on your own device or settings.

This article is a set of steps to try, easiest first.

Bottom line: suspect “device, settings, location, network,” in that order

The cause is usually one of these four.

1. A temporary glitch on the device
2. A settings problem
3. A problem with where you are
4. A problem with the network (the carrier’s side)

Try them from least effort to most, and narrow it down.

Step 1: Turn airplane mode on and off (10 seconds)

Turn airplane mode on for about 10 seconds, then switch it back off.

Your phone re-acquires the signal. Surprisingly often, this fixes it.

Step 2: Restart

If airplane mode doesn’t fix it, power off and back on.

It helps when the device is temporarily acting up.

Step 3: Reseat the SIM

If you use a SIM card, power off, take the SIM out, and put it back in. If it’s a contact problem, this can fix it.

If you use eSIM, check in the settings screen that the line is enabled.

Step 4: Reset network settings

If it’s still not fixed, try resetting network settings.

Note: saved network settings, such as Wi-Fi passwords, will be erased. Write down anything you need before you do this.

The menu location and name differ by device and OS version. Look in the settings screen for “Reset” or “Network.”

Step 5: Update the OS and carrier settings

If an OS or carrier settings update is available, install it. If you leave things outdated, bugs can stick around.

Step 6: Try changing your location

If the device and settings look fine, suspect the location.

• Inside buildings, signal tends to get weaker. Try moving to a window or going outside
• Underground, or deep inside reinforced concrete, signal has a hard time getting through

How well signal passes through walls changes with frequency. I explain it with a drum and a violin analogy in the platinum band article.

Step 7: Does your device support the network’s frequencies?

Overseas models and used devices may not support the bands used in Japan. I’ve put together how to check frequency bands.

Step 8: Try another SIM (isolating the cause)

If you have a different SIM, swapping it in lets you isolate the problem.

• Also bad in the same place with the other SIM → possibly the device or the location
• Fine with the other SIM → possibly the original line or SIM

A recent change: your coverage area may have changed

Sometimes your carrier’s coverage area changes, and places that used to get signal now get it less well.

For example, for Rakuten Mobile, the au roaming arrangement ended at the end of September 2026. The impact depends on your area. I go through what’s been reported in another article.

Of course, this isn’t necessarily the reason for your weak signal. Isolate the cause with the steps above first, then suspect this.

If it’s still not fixed

If you’ve tried all this and it’s still not fixed, contact your carrier.

It speeds things up if you tell them the following.

• Since when, where, and what symptoms (no service, slow, calls dropping, and so on)
• What you’ve tried (airplane mode, restart, reseating the SIM, and so on)
• Your device model

Summary

• When the signal is weak, suspect device, settings, location, and network, in that order
• Start with airplane mode, a restart, and reseating the SIM. Try the easy ones first
• Resetting network settings erases your saved Wi-Fi info, so be careful
• Changing location or trying another SIM helps isolate the cause
• If it’s not fixed, tell your carrier the symptoms and what you’ve tried, and contact them

With signal trouble, isolating the cause is the shortcut, before you rush to change phones or switch carriers.

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This article contains machine translation. For official terms, please refer to the multilingual pages on the official Rakuten Mobile website.

If you have concerns about Rakuten Mobile's coverage area or signal conditions, you can inquire through the official signal improvement survey request form .