How to receive SMS when you have no signal

You're in a basement, a rural area, on a plane's Wi-Fi or abroad without roaming, and an app wants to text you a code. With no bars, a normal SMS just waits until you're back in range. Here's what actually works when you have internet but no mobile signal, and what to do if the code is for your own number versus a new account.

Why SMS doesn't arrive without signal

A standard text message is delivered by your carrier's mobile network to the SIM in your phone. If the phone can't reach a cell tower, the carrier holds the message and retries for a while. It's delivered when you get signal back, or it expires if that takes too long. Codes often expire within minutes, so a late SMS may be useless.

Option 1: turn on Wi-Fi Calling

Many carriers in the US, Canada and the UK support Wi-Fi Calling, which also delivers regular SMS over Wi-Fi. When it's on, texts to your own number can arrive even with no signal, as long as you're connected to Wi-Fi.

On an iPhone, look for Wi-Fi Calling under Settings > Phone (or Settings > Cellular). On Android, it's usually in the Phone app settings or under Network & internet > Calls & SMS. Your plan and phone must support it, and some carriers limit it while abroad.

• Works with your real number, so it's the right fix for codes from your bank or existing accounts.
• Needs carrier support and a compatible phone.
• Set it up before you lose signal, since enabling it can require a confirmation.

Option 2: messaging apps over Wi-Fi

iMessage between iPhones, RCS chats in Google Messages and apps like WhatsApp or Telegram all run over the internet. They work on Wi-Fi with no signal. They don't help with SMS codes sent by other apps, though, because those are plain text messages from a short code or a business number.

Step by step

1. Connect to Wi-FiAny working internet connection is enough, even if your phone shows no bars.
2. Open the Noir SMS dashboardSign in from your phone's browser or a laptop and add funds if needed.
3. Rent a number for the appChoose the service and a country. The number is reserved for you for 20 minutes.
4. Read the code on screenEnter the number in the app. The SMS shows up in the dashboard, and if none arrives you're refunded automatically.

Option 3: an online number for a new sign-up

If the code is for a new account and the number doesn't have to be yours, you can skip the signal problem entirely. Rent a temporary online number, enter it in the app, and the SMS shows up in your browser over any connection: hotel Wi-Fi, a laptop on a plane, or a phone with no SIM.

This doesn't work for accounts already linked to your own number. Those codes go to your number, so use Wi-Fi Calling or wait until you have signal.

Which option fits your situation

Tips to avoid the problem next time

• Turn on Wi-Fi Calling at home, before you need it.
• Add an authenticator app to important accounts, so you don't depend on SMS.
• Save backup codes for accounts that offer them.
• Before a trip, check whether your carrier allows Wi-Fi Calling abroad.