Do Faraday Bags Block GPS? How It Actually Works

Faraday bags get talked about a lot, especially when the topic is GPS tracking, privacy, or digital security. But do Faraday bags actually block GPS, or is that just marketing hype?

Short answer: yes, a properly made Faraday bag can block GPS. The longer answer is more interesting, and it depends on how GPS works, how Faraday shielding works, and how the bag is designed.

This guide breaks it all down in plain English.

What Is GPS and How Does It Track You?

GPS stands for Global Positioning System. It works using a network of satellites orbiting the Earth.

Your phone, car, or tracking device does not send signals up to the satellites. Instead, it receives signals from multiple satellites at once. By measuring timing differences, the device calculates its exact location.

Key points to know:

GPS signals are radio waves
They are very weak by the time they reach Earth
GPS requires a clear signal to work accurately

Because GPS signals are weak, they are easy to disrupt.

What Is a Faraday Bag?

A Faraday bag is a signal-blocking pouch lined with conductive material. It works as a portable Faraday cage.

When a device is placed inside and the bag is sealed, the conductive lining blocks electromagnetic signals from entering or leaving.

That includes:

GPS
Cellular signals
WiFi
Bluetooth
RFID
NFC

The goal is simple: isolate the device from the outside world.

Do Faraday Bags Block GPS Signals?

Yes, Faraday bags can block GPS signals.

When a GPS-enabled device is inside a properly sealed Faraday bag, it cannot receive satellite signals. Without those signals, it cannot determine or report its location.

This works because:

GPS uses radio frequencies
Faraday shielding blocks radio frequencies
GPS signals are especially weak

If the bag is well-designed, GPS tracking stops completely while the device is inside.

Why GPS Is Easier to Block Than You Think

People often assume GPS is powerful or hard to interfere with. In reality, it is one of the easiest signals to block.

Reasons include:

GPS satellites are extremely far away
Signals lose strength traveling through the atmosphere
Buildings, metal, and terrain already interfere with GPS

That is why GPS struggles indoors, underground, or in dense urban areas.

A Faraday bag creates a controlled version of that interference.

When Faraday Bags Fail to Block GPS

Not all Faraday bags are created equal.

A bag may fail to block GPS if:

The bag is not fully sealed
The conductive lining is low quality
The opening is folded instead of properly closed
The device is too close to the opening

Even a small gap can let GPS signals leak through.

This is why closure design matters as much as the shielding material.

Does Phone GPS Still Work in a Faraday Bag?

No. When your phone is inside a properly sealed Faraday bag:

GPS stops working
Maps cannot update your location
Location-based apps fail
Find My and similar tracking features go offline

The phone may still show your last known location, but it is no longer updating in real time.

Once removed from the bag, GPS functionality returns immediately.

Can Law Enforcement or Satellites Track Through a Faraday Bag?

This is a common question.

Satellites, cell towers, and GPS systems cannot track a device that is fully shielded inside a Faraday bag.

There is no hidden backdoor signal and no special satellite that can see through proper electromagnetic shielding.

Physics applies to everyone.

GPS vs Cellular Tracking: What Gets Blocked?

A quality Faraday bag blocks more than just GPS.

It also blocks:

Cellular connections (4G, 5G)
WiFi signals
Bluetooth
RFID and NFC chips

This means:

No location tracking
No remote access
No data transmission
No wireless commands

If a signal relies on radio waves, it gets blocked.

How to Test If a Faraday Bag Blocks GPS

You can test GPS blocking yourself in under a minute.

Steps:

Open a maps app on your phone
Confirm your live location is updating
Place the phone inside the Faraday bag
Seal the bag completely
Wait 30 to 60 seconds

If the bag works:

The location freezes
The GPS accuracy disappears
No movement is tracked

For best results, test outdoors where GPS normally works well.

Why People Use Faraday Bags for GPS Blocking

People use Faraday bags for many legitimate reasons. This is exactly why OffGrid designs Faraday bags for real-world use, not just lab conditions.

Common use cases include:

OffGrid customers commonly use OffGrid Faraday Bags in these situations because they are built with multi-layer shielding and secure closure systems that prevent signal leaks in everyday environments.

Privacy protection
Preventing unwanted tracking
Securing devices during travel
Shielding spare phones or car keys
Digital security and data protection

Blocking GPS is often just one part of a broader privacy strategy.

Are Faraday Bags Legal?

In most countries, Faraday bags are legal to own and use.

They do not interfere with public infrastructure. They simply block signals to and from devices you own.

Laws vary by location, so it is always smart to understand local regulations, especially in restricted environments.

What to Look for in a GPS-Blocking Faraday Bag

If GPS blocking matters to you, look for these features. OffGrid Faraday Bags are designed around all of the points below, with a focus on reliability rather than gimmicks.

High-quality conductive shielding
Multiple layers of signal-blocking material
A secure sealing mechanism
Independent lab testing or verification
Proper sizing for your device

A poorly designed bag may block some signals but leak GPS.

OffGrid Faraday Bags use reinforced seams, overlapping signal-blocking closures, and multiple shielding layers to ensure GPS, cellular, WiFi, and Bluetooth signals stay blocked when the bag is sealed.