How to Choose a SIM Card for a 4G Pet Tracker

Quick answer: choosing a SIM card for a 4G pet tracker is not just a matter of picking a cheap mobile plan. The tracker, regional hardware version, LTE bands, carrier network, APN, SIM PIN settings and required services all need to work together. Some trackers need only mobile data during normal use, while others also use SMS for setup or diagnostics, or voice service for calling features.

If a tracker already has a built-in or managed SIM, you normally should not add a separate SIM at all. If it uses your own SIM, follow the compatibility checks below before buying a plan.

Start With the Tracker, Not the SIM

The most common mistake is choosing a SIM plan first and checking the tracker afterward.

Start by identifying how the tracker connects. A current pet-tracking product may use:

If you are still deciding which connection style fits your pet, use the VerdantTrace Pet Tracker Finder or compare the current lineup on the Compare Pet Trackers page before buying a SIM.

The 6-Part Compatibility Check

1. Exact tracker model

Do not choose a SIM from appearance alone. Two trackers with similar housings can use different cellular modules, different SMS commands and different supported bands.

2. Regional hardware version

Confirm whether your unit is an EU/Eurasia, Americas, Asia or another regional version. A SIM card cannot add frequency bands that are missing from the tracker hardware.

3. Cellular technology

Look for the actual modem technology, such as LTE Cat 1, Cat 1 bis, LTE-M/Cat M1 or NB-IoT. These are all cellular technologies, but they are not automatically interchangeable across carriers and countries.

4. LTE frequency bands

Compare the bands listed for the exact tracker version with the bands used by the intended carrier where your pet will actually use the device.

5. Required mobile services

Determine whether the tracker needs mobile data only, SMS for setup or diagnostics, voice service for calling features, or more than one of these.

6. Carrier and plan rules

Ask whether the plan permits use in a GPS tracker or IoT device. A SIM can work perfectly in a phone but still be unsuitable for the tracker or plan type.

Check the 4G Network Technology

The word 4G is not enough by itself to confirm compatibility.

LTE Cat 1 and Cat 1 bis

These technologies are widely used in mobile IoT devices that need regular data communication while moving through cellular coverage. In a pet tracker, that can support location uploads, geofence alerts, route history and remote app commands.

LTE-M / Cat M1

LTE-M is designed for connected devices that benefit from lower power consumption and mobile network support. The local operator must support the technology and the device profile being used.

NB-IoT

NB-IoT is optimized for low-bandwidth IoT communication. Its mobility, roaming, SMS and voice behavior can differ from a conventional Cat 1 tracker, so compatibility must be confirmed for the exact device and network.

Match LTE Bands and Regional Versions

A tracker and carrier need usable LTE bands in common. One theoretical overlapping band is not always enough for a good real-world experience because carriers may use different bands in different cities, rural areas and network layers.

When a model has separate regional versions, choose the version intended for the country where the tracker will normally be used. If you are buying before travel, check both the home country and the destination.

Data vs SMS vs Voice: What Does Your Tracker Need?

This is one of the most important checks before choosing a GPS tracker SIM card.

That is why a plan described as “perfect for GPS trackers” is not automatically right for every pet tracker.

Can You Use a Data-Only SIM in a GPS Tracker?

Sometimes. A data-only SIM can be suitable when the tracker only needs cellular data during normal operation and you do not need SMS or mobile voice functions.

However, some GPS trackers use SMS commands to:

• set or change the APN;
• query device status;
• configure a server or other network parameters;
• diagnose an offline device;
• change selected device settings.

If your tracker depends on SMS for any of those tasks, a SIM with no SMS service may make setup or troubleshooting harder. Some devices can be configured first with an SMS-capable SIM and then switched to a data-only SIM, but that depends on the model and should only be done when the device manual or support team confirms the procedure.

How Much Mobile Data Does a GPS Tracker Use?

There is no universal data allowance that fits every pet GPS tracker.

Usage can change with:

• location upload interval;
• live-tracking frequency;
• signal quality and network retries;
• activity or status uploads;
• firmware behavior;
• remote commands and connected features.

A low-data plan may be enough for a simple tracker that sends small location packets, while higher-frequency tracking or additional connected features can use more. Start from the manufacturer’s recommendation, choose reasonable headroom, and review the real SIM usage after activation.

APN: Why a Working SIM Can Still Show Offline

APN stands for Access Point Name. It tells the device how to establish a mobile-data connection through the carrier.

A SIM can be active and work normally in a smartphone while the tracker remains offline because the phone may configure its carrier settings automatically, while the tracker may require an APN to be entered manually or sent by SMS.

Depending on the carrier, APN information can include:

• APN name;
• username;
• password;
• authentication settings;
• MCC/MNC or other network values on certain tracker command sets.

For example, a carrier may publish an APN plus username and password, while another carrier may use an APN with blank credentials. The SMS command format used to enter those values is a separate question and depends on the tracker model.

Disable the SIM PIN When Required

Many compact trackers do not have a screen or keypad where a SIM PIN can be entered during startup.

If your model requires an unlocked SIM and PIN protection is enabled, the device may fail to register normally on the mobile network.

A typical process is:

Insert the SIM into a compatible phone
→ Open the phone's SIM/security settings
→ Disable SIM PIN / SIM lock
→ Power off the tracker
→ Reinstall the SIM
→ Restart the tracker

Menu names vary by phone manufacturer and operating system. Follow the instructions for your phone and tracker.

SIM Works in a Phone but the Tracker Is Offline

This is one of the most common and most confusing connectivity problems.

If mobile data works in a phone but the pet tracker remains Offline or Not Enabled, check the connection chain in this order:

1. SIM activation: confirm the plan is active and has data.
2. SIM PIN: disable it if the tracker requires an unlocked SIM.
3. Regional version: confirm the tracker hardware is intended for the country.
4. LTE bands: verify overlap with the carrier.
5. Carrier/device policy: confirm the plan allows GPS/IoT use.
6. APN: enter the carrier-provided APN using the method for your exact tracker.
7. GPRS/mobile-data state: use the model-specific status command if available.
8. App/server settings: verify that the device is registered to the correct account/region/platform.
9. Outdoor test: once cellular connectivity is established, test location outdoors with clear sky visibility.

If another known-compatible SIM works in the same tracker, the original SIM, plan, APN or carrier compatibility becomes the more likely problem.

Cellular Signal Does Not Always Mean Internet Access

A device can register on a cellular network or show a signal indicator without successfully creating the mobile-data session needed by the tracking app.

This is why “the tracker has bars” does not automatically prove that the APN, data plan and app connection are working.

When the tracker has apparent cellular signal but stays offline, focus on the data path:

network registration → data service → APN → GPRS/mobile-data connection → tracker server/app.

Why SMS Commands May Not Reply

If your tracker supports SMS commands but does not reply, do not immediately assume the hardware has failed.

Check:

• whether the SIM plan includes SMS;
• whether the tracker is registered on the cellular network;
• whether the command syntax exactly matches the model manual;
• whether the command is case-sensitive;
• whether the command requires a master/admin number first;
• whether the device is roaming and the SIM supports SMS in that situation;
• whether the device firmware/network combination supports SMS on the current carrier.

Some trackers also fail to reply when a status response becomes too long or when the network path is unstable. In that case, use the model-specific diagnostic method provided by support.

SMS Commands Are Model-Specific

This is important: there is no universal APN SMS command that should be sent to every VerdantTrace or third-party GPS tracker.

Different firmware families use different separators, parameters and prerequisites.

For example, the V41-family status command can report items such as firmware version, device ID, IMEI, server, control number, upload interval, battery, GPRS/network state, GPS and Wi-Fi status. That makes the status response much more useful to support than simply saying “the app is offline.”

What to Check After Changing SIM Cards

Changing from one carrier to another can introduce a new APN, new credentials, a different MCC/MNC, different roaming behavior or different network bands.

If the tracker worked before the SIM change but goes offline afterward:

1. confirm the new SIM is activated;
2. test mobile data in a phone;
3. disable the SIM PIN if required;
4. get the new carrier APN;
5. check whether the tracker needs SMS to update the APN;
6. apply the new APN using the exact model-specific method;
7. restart the tracker if required by the manual;
8. wait for the device to register and test outdoors.

Do not assume the old APN will work with the new SIM.

4G Data, SMS and Voice Can Behave Differently

A tracker being described as “4G” does not automatically mean that data, SMS and voice are handled in exactly the same way on every carrier.

As mobile operators retire older 2G and 3G networks, some IoT devices can continue using LTE data while SMS or voice behavior depends on the device module, carrier implementation, roaming agreement and network configuration.

This matters most when a tracker relies on SMS commands or cellular calling. If app tracking works but SMS or voice does not, treat those as separate compatibility checks rather than assuming the entire 4G connection is broken.

Roaming and International Use

A pet tracker that works at home may not automatically work in another country.

Before travel, check:

• destination LTE bands and cellular technology;
• whether the SIM plan allows data roaming;
• whether SMS roaming works if the tracker uses SMS commands;
• whether voice roaming/VoLTE is supported if the tracker has calling features;
• whether the APN changes when roaming;
• whether the tracker’s regional hardware supports the destination network.

A local SIM can reduce roaming cost, but it cannot solve a hardware-band mismatch.

What to Send Support When the Tracker Still Will Not Connect

If the SIM is active, the PIN is disabled, the APN is correct and the tracker is still offline, avoid changing multiple advanced settings at random.

Send support the following information:

• Exact tracker model.
• Regional version.
• Country where the device is being used.
• SIM carrier/provider.
• SIM plan type: data only, data + SMS, or data + SMS + voice.
• Whether mobile data works when the SIM is tested in a phone.
• Whether the SIM PIN has been disabled.
• Carrier-provided APN, username and password if applicable.
• Screenshot of the App showing Offline / Not Enabled or another error.
• Device status reply from the model-specific diagnostic command, when available.

Selected devices may use commands such as INFO# or ts# to retrieve diagnostic information, but you should only use the command confirmed for your exact model.

You can also start from the VerdantTrace Troubleshooting Center or Support Center.

Final SIM Card Checklist for a 4G Pet Tracker

Choose the Connection Style Before You Choose the Plan

The best SIM card for a 4G pet tracker is not automatically the cheapest plan or the biggest smartphone data package. It is the SIM and service combination that matches the tracker hardware, required features, carrier network and places where your pet actually moves.

If you want carrier choice and are comfortable checking APN and network compatibility, an own-SIM tracker can be a flexible option. If you prefer fewer cellular setup steps, a built-in or managed-connectivity tracker may be easier—but you should still check coverage, service terms and supported countries.

Frequently Asked Questions

What SIM card do I need for a 4G pet tracker?

Choose a SIM that matches the tracker’s SIM size, cellular technology, regional version and LTE bands. Then confirm whether the tracker needs mobile data only, SMS, voice, or a combination, and verify the APN and plan rules with the carrier.

Can I use any phone SIM card in a GPS tracker?

No. A phone SIM can work in a smartphone but fail in a tracker because of LTE-band differences, APN configuration, SIM PIN settings, plan restrictions or unsupported network technology.

Can I use a data-only SIM in a GPS tracker?

Sometimes. It can work when the tracker only needs mobile data for the functions you use. If the tracker relies on SMS for APN setup, diagnostics or remote commands—or voice for calling—a data-only plan may remove those functions.

Does a GPS tracker need SMS?

Not every tracker does. Some use SMS only during setup or troubleshooting, while others do not need SMS at all. Check the exact model manual before choosing a data-only plan.

Why does my GPS tracker show Offline or Not Enabled?

Common causes include an inactive SIM, enabled SIM PIN, wrong APN, incompatible regional version or LTE bands, carrier/device restrictions, missing data service, app/server settings, or a model-specific configuration issue.

Why does the SIM work in my phone but not in the tracker?

A phone can automatically apply carrier settings that a tracker cannot. The tracker may still need the correct APN, compatible LTE bands, an unlocked SIM, an allowed device plan and the correct app/server configuration.

Why does my tracker show cellular signal but stay offline?

Network registration and internet access are not the same thing. The device can see or register on a cellular network but still fail to establish the data connection required by the tracking server or app.

Why is there no reply to my GPS tracker SMS command?

Check whether the SIM supports SMS, the device is registered on the network, the command syntax matches the exact model, a master/admin number is required, and SMS works on the current carrier or roaming network.

What is the APN on a GPS tracker?

The APN is the carrier setting the tracker uses to establish its mobile-data connection. Obtain it from the SIM provider. Depending on the tracker, it may be entered in an app, configured automatically or sent with a model-specific SMS command.

Do I need to disable the SIM PIN?

Many compact GPS trackers require the SIM PIN to be disabled because they do not provide a screen for entering it after startup. Follow the instructions for your exact tracker.

How much data does a pet GPS tracker use?

There is no universal number. Usage depends on location-update frequency, live tracking, signal quality, firmware and connected features. Start with the manufacturer’s guidance and review real usage after activation.

Can a 4G tracker have working data but broken SMS or voice?

Yes. Data, SMS and voice can rely on different network capabilities. This becomes especially important as carriers retire older network technologies and move IoT communication to LTE-based implementations.

Can I use my pet tracker in another country?

Possibly. Confirm the destination LTE bands, roaming permission, data/SMS/voice requirements, APN behavior and regional hardware compatibility before travel.

Related VerdantTrace Resources

• Compare Pet Trackers
• Find My Pet Tracker
• Troubleshooting Center
• Support Center