Quick Summary

• Your phone now needs 4G + VoLTE for calls and texts in NZ after the 3G shutdown.
• Some overseas models and old SIM cards can no longer register properly on NZ networks.
• Follow this checklist from network settings to hardware checks before you decide to replace the phone.

Why “SOS Only” / “No Service” Became So Common After NZ 3G Shutdown

Before the 3G shutdown, many phones used 3G for voice calls and only used 4G for data.
Now in New Zealand, voice, text and data all depend on 4G (and VoLTE). If your phone cannot speak the “4G voice language” of NZ carriers, the network rejects it. The phone then shows “SOS Only” or “No Service” even though the signal bars may look fine.

We see this every week at EziRepair in Christchurch and Auckland: overseas models, old SIM cards, and phones with marginal baseband hardware suddenly stop working properly after the network updates.

For a deeper background on what changed in NZ, see our guide

why New Zealand is shutting down 3G
.

Checklist: What To Do When Your Phone Shows “SOS Only” or “No Service” After 3G Shutdown

1. Confirm the issue is the phone, not the area

• Test another phone with the same SIM in the same place.
• Test your phone with a different SIM from the same or another NZ carrier.
• If every phone struggles in that location, it is a coverage issue, not your handset.

2. Check VoLTE and SIM / eSIM status

After 3G shutdown, your phone must support 4G VoLTE with your NZ carrier.
If VoLTE is disabled, or your SIM/eSIM profile is outdated, registration fails and the phone falls back to “SOS Only”.

On iPhone

• Go to Settings > Mobile > Voice & Data.
• Select 4G and make sure VoLTE is turned on (if the toggle exists).
• If you never see a VoLTE option, your model or carrier profile may not support it properly in NZ.

On Android (general)

• Open Settings > Connections > Mobile networks (wording varies by brand).
• Look for VoLTE calls or 4G Calling and turn it on if available.
• Make sure Preferred network type is set to include 4G/5G (LTE/5G).

If the SIM or eSIM itself is old or corrupted, VoLTE may fail. Our separate guide

how to check your SIM and VoLTE after the NZ 3G shutdown

explains how to confirm this with your carrier.

3. Make sure your model supports NZ 4G bands (especially Band 28)

Even if VoLTE exists, the phone still needs the right 4G bands to work in New Zealand. Many overseas models lack Band 28, which NZ carriers use heavily for indoor coverage.

Typical NZ 4G bands:

• Spark / One NZ: LTE Bands 3, 7, 28
• 2degrees: LTE Bands 1, 3, 28

If your phone has poor or no support for Band 28, it might work outdoors but show “SOS Only” or “No Service” as soon as you step inside a building. This is common on some imported models from the US, China, and parts of Europe.

4. Reset carrier and network settings

After big carrier updates or 3G shutdown changes, phone profiles can break. A clean network reset often helps.

On iPhone

• Go to Settings > General > Transfer or Reset iPhone > Reset.
• Tap Reset Network Settings (you will re-enter Wi-Fi passwords afterwards).

On Android

• Open Settings > General management > Reset (or similar menu).
• Choose Reset network settings or Reset mobile network settings.

5. Test Wi-Fi Calling: does the phone behave only on Wi-Fi?

If your phone cannot stay on the mobile network indoors, Wi-Fi Calling can keep you reachable while you investigate the underlying problem.

• Enable Wi-Fi Calling in your carrier’s settings (and in the phone settings).
• Connect to a strong Wi-Fi network and try a call.
• If calls work on Wi-Fi but you quickly drop to “SOS Only” on mobile, your issue is most likely bands/coverage or VoLTE compatibility, not a total hardware failure.

6. Rule out IMEI blacklist and carrier lock

A phone that has been reported lost/stolen or blocked for unpaid bills can be placed on an IMEI blacklist. In many cases, that phone will show “No Service” or fail to register properly even if the SIM is fine.

• Check with your NZ carrier if the IMEI is clean.
• Ask whether the phone is carrier locked to an overseas provider (US, Japan, Korea, etc.).
• If it is carrier-locked or blacklisted, software settings will not fix it.

7. Consider hardware faults: baseband, antenna, or board damage

If your phone passes all the checks above, but still sits on “SOS Only” or “No Service”, the problem can be on the main board:

• Baseband / network IC faults (very common on some iPhone 11–12 boards).
• Micro-cracked solder joints after drops or bends.
• Antenna bracket or coax damage from previous repairs.

These issues need board-level diagnosis. At EziRepair we check under magnification, test with known-good antennas and SIMs, and then quote you on whether board repair or replacement is realistic for the value of the phone.

Real-World Patterns We See in Christchurch and Auckland

• Imported iPhones from Asia or the US that worked fine for years, then suddenly lose service after a carrier update or the 3G shutdown.
• Phones that only work outside buildings because they lack Band 28, so indoor coverage collapses to “SOS Only”.
• iPhone 12 boards coming in with “No Service” where the baseband section has taken a hit or has marginal solder joints.
• Old SIM cards from many years ago that do not behave well with modern 4G/5G and VoLTE profiles.

In many cases, a new SIM, proper VoLTE setup, or a clean network reset revives the phone. In others, especially with overseas models, we help customers decide whether repair is worth it or if it is time to move to a NZ-friendly model.

When Is It Worth Fixing, and When Should You Change Phones?

As a rough rule:

• If the only issue is settings, SIM, or carrier profile, it is nearly always worth fixing.
• If the phone is blacklisted or permanently carrier-locked, it is usually better to move on.
• If it needs board-level baseband repair on an older or heavily damaged phone, we will compare the repair cost with the price of a good NZ-compatible replacement.

Bring your phone in and we can run through this checklist with our own test SIMs, tools, and experience, so you do not have to guess.

Related Guides for NZ Customers

• 
  Why your phone shows “SOS Only” or “No Service” in New Zealand (and what it means)
  
• 
  How to check your SIM and VoLTE settings after the NZ 3G shutdown
  
• 
  Why New Zealand is shutting down 3G and what it means for your phone
  

Need Your “SOS Only” / “No Service” Phone Checked in Person?

If you are tired of guessing why your phone stopped working after the NZ 3G shutdown, we can test it with our own SIMs, tools, and experience and then give you a clear repair or replacement recommendation.

EziRepair Christchurch — Phone: 03 343 1078

EziRepair Auckland (Westgate) — Phone: 09 392 0039

Website: www.ezirepair.co.nz