A phone that cannot communicate with the outside world cannot simply be ordered by a website to report a new GPS position. But that does not mean every offline-phone search is hopeless: recent positions and offline-finding networks can sometimes help.
A phone can be offline because mobile data is disabled, there is no coverage, Wi-Fi is unavailable, airplane mode is on, the SIM has been removed or the battery is dead. Those situations are not equivalent.
GPS reception itself is passive: the receiver listens to satellite signals. Sending the resulting position to you requires some form of communication. A conventional app cannot upload a fresh point while the phone has no usable path to a server.
Google's Find Hub can show information from the device and, on supported configurations, from the broader Find Hub network. Google's current documentation also describes encrypted recent locations and offline finding capabilities for supported Android devices and accessories.
That means an 'offline' label should not stop you from checking. The service may have a last-known position or other useful information even when it cannot make a fresh direct connection.
When a device is genuinely powered down, ordinary third-party apps are not running. A website cannot wake an arbitrary handset through its telephone number, IMEI or email address and ask Android for GPS coordinates.
Some modern device-finding systems have hardware and operating-system features designed specifically for offline finding. Those capabilities belong to the device platform; they are not something a random tracker website can add retroactively.
For a complete sequence, see How to find a lost Android phone.
LocationOf can continue to be useful during temporary connectivity gaps if the installed app records positions and later uploads them when connectivity returns. It cannot, however, generate new server-side location points from a phone that is switched off.
The important distinction is between recording locally and uploading later versus magically locating a silent phone from the web. Only the first is a normal GPS-tracker capability.
The most important word on an offline-phone map is often the timestamp. A point recorded at 18:20 may be perfectly accurate for 18:20 and completely wrong as a description of where the phone is at 19:00. Good recovery decisions therefore use both position and time.
If several recent points form a route and then stop, the final point can suggest where connectivity or power disappeared. It does not prove the phone stayed there. The device may have continued moving in a pocket, vehicle or bag after the last successful upload.
This distinction also applies to third-party trackers such as LocationOf. A web dashboard can only display data that was recorded and delivered. When a phone reconnects, an app may upload older locally stored points; those should retain their original capture times rather than being mistaken for new live positions.
Yes, in some situations. “No mobile data” is only one kind of offline state. The device may connect to Wi-Fi later, or a platform-specific offline-finding network may contribute information on supported hardware. A phone with its SIM removed can still have Wi-Fi and satellite positioning capabilities.
Conversely, a phone can have excellent GPS reception and still be invisible to a remote web page if it has no path to transmit the result. Satellite positioning answers “where am I?” locally; internet connectivity answers “how do I tell somebody else?” remotely.
For the underlying technology, see Does GPS work without internet? and Does GPS work without a SIM card?.
Be cautious with services claiming that a powered-off phone can be located simply by entering its phone number or IMEI and paying a fee. A genuinely powered-down handset is not running an ordinary Android application that a random website can contact. Platform vendors can build special offline-finding features into supported devices, but that does not create a universal public API for strangers.
Before paying any “locator” service, ask what authorized technical relationship it has with the target device. Is there an app already installed? Is the phone signed into an account you control? Is there paired hardware? Is the service your mobile carrier? If none of those applies, a claim of precise live GPS should be treated very skeptically.
For identifier-specific explanations, see phone-number tracking and IMEI tracking.