Quick Summary: What You Should Check First

• Check if your house is in a coverage “shadow” zone, even when the neighbourhood has good 4G/5G.
• Move your router and modem to a better spot so Wi-Fi covers more of the house.
• Test different mobile networks (Spark, One NZ, 2degrees) using another SIM or another phone.
• Turn on Wi-Fi Calling so your phone uses your home internet for calls and texts.
• Have the phone inspected if others have good signal at your place but your device always struggles.

Why This Happens So Often in New Zealand Homes

At our repair shops in Christchurch and Auckland, we see this problem all the time:
the phone shows weak bars, “No Service,” or “SOS only” at home, but as soon as you step outside or drive down the road, it works again.

In many cases, there is nothing “wrong” with the phone.
The problem sits somewhere between the mobile tower, the building materials of your house, your router placement, your SIM card settings, and how your device is configured.

The good news: if your Wi-Fi is strong, you have several options before you even think about changing phones.

1. Start With the House and the Coverage, Not the Phone

Mobile signal comes from a tower outside. It has to pass through air, other houses, trees, and finally your walls, roof, and windows.
Wi-Fi comes from a box inside your house. So it is common to have great Wi-Fi and poor mobile reception in the same room.

Check if you are in a weak indoor zone

• Does the signal drop only in certain rooms, like the garage, hallway, or downstairs bedroom?
• Is your house full of steel framing, foil insulation, or concrete walls?
• Do you get more bars when you stand near a window or on the deck?

If the signal improves as soon as you step outside or move closer to the window, your house is acting like a shield.
In that case, your goal is to work around the building, not fight the phone.

2. Fix the Router and Modem Placement so Wi-Fi Helps Everywhere

You already have strong Wi-Fi, which is good. But often the router sits:

• Inside a metal cabinet or hallway cupboard.
• On the floor behind the TV.
• At one far end of the house.

For the best experience with both Wi-Fi and Wi-Fi Calling, try:

• Placing the router higher up (on a shelf or wall bracket).
• Moving it closer to the centre of the house.
• Keeping it away from thick walls, fridges, and metal surfaces.
• Adding a mesh Wi-Fi unit if your home is long or two-storey.

Once the Wi-Fi coverage is solid across the house, you are ready for the most powerful fix in this article: Wi-Fi Calling.

3. Test a Different Mobile Provider at the Same Spot

New Zealand has three main mobile networks: Spark, One NZ, and 2degrees.
A house can have terrible coverage on one of them and decent coverage on another, even on the same street.

The simplest way to compare

• Borrow a friend or family member’s phone that uses a different provider.
• Stand in the same room in your house (where your signal is weak).
• Check bars, try a call, and try a speed test over mobile data.

If their phone on another network works much better than yours in the same spot, you have strong evidence that the problem is the carrier, not your device.
In that case, changing plan or provider is often more effective than buying a new phone.

If all networks struggle inside the house, Wi-Fi Calling becomes even more important.

4. Turn On Wi-Fi Calling – The Game Changer for Indoor Signal

Wi-Fi Calling lets your phone use your internet connection to make and receive calls and texts.
When it is enabled and supported by your provider, the phone no longer depends on strong indoor mobile signal.

How to enable Wi-Fi Calling on iPhone

1. Open Settings.
2. Tap Mobile (or Cellular).
3. Tap Wi-Fi Calling.
4. Turn on Wi-Fi Calling on This iPhone.
5. Follow any on-screen prompts from your carrier.

How to enable Wi-Fi Calling on Samsung Galaxy

1. Open Settings.
2. Tap Connections.
3. Look for Wi-Fi Calling.
4. Turn it on.

Some models or plans may require VoLTE and Wi-Fi Calling support from the provider.
If your phone is older or from overseas, compatibility can be an issue. For more details on VoLTE and the 3G shutdown in New Zealand, see:

• 
  How to Check Your SIM and VoLTE After the NZ 3G Shutdown
  
• 
  Why New Zealand Is Shutting Down 3G (and What It Means for Your Phone)
  

Once Wi-Fi Calling is set up correctly, many customers tell us their “signal problem at home” disappears overnight.

5. When the Phone Itself Is the Problem

Sometimes, the device really is faulty. If everyone else in your house has good signal on the same network, but your phone always shows weak bars, drops calls, or goes to “SOS only,” it is time to inspect the hardware and settings.

Common device-side causes we see in our workshop

• Water damage or corrosion around the antenna and RF ic area on the main board.
• Back glass or frame damage that has broken or loosened the antenna contacts.
• Poor-quality third-party housing or frame replacements blocking signal.
• Overseas models that do not support New Zealand 4G/5G bands properly.
• Phones on a blocked or stolen list that show “No Service” or “SOS only.”

If your phone shows “SOS only” or “No Service” even in areas where other phones are fine, this guide will help you understand that situation more deeply:

Why Your Phone Shows “SOS Only” or “No Service” in New Zealand (and What It Means)

When we inspect a phone, we do more than just “turn it off and on again.”
We check the antenna contacts, look for corrosion under a microscope, test different SIM cards, and confirm if the IMEI is clean.

When to Bring Your Phone in for a Check

You should consider a professional check if:

• Other phones have decent signal in your house, but yours always struggles.
• Wi-Fi Calling does not stay active even with strong Wi-Fi.
• The phone has a history of drops, screen replacements, or water damage.
• You suspect an overseas model or blocked device issue.

We will test your device, explain what is happening in plain language, and recommend whether repair, network change, or a new phone makes more sense.

Need Help With Weak Signal at Home?

If you are in Christchurch or Auckland and your phone only misbehaves at home, we can help you sort out whether it is:

• a coverage issue,
• a router or Wi-Fi placement problem,
• a SIM or VoLTE / Wi-Fi Calling setting, or
• a phone hardware fault.

Bring your phone in, or call us first and we can guide you through some quick checks over the phone.

EziRepair – Christchurch & Auckland

Related Articles About Network Issues in New Zealand

• 
  Why Your Phone Shows “SOS Only” or “No Service” in New Zealand (and What It Means)
  
• 
  How to Check Your SIM and VoLTE After the NZ 3G Shutdown
  
• 
  Why New Zealand Is Shutting Down 3G (and What It Means for Your Coverage