Most hikers think about emergency communication in terms of “have I got signal or not,” and treat 000 as either fully available or completely useless depending on the bars on their phone. That’s not quite how it works. Two things happen behind the scenes on a 000 call that most people have never heard of, and both exist specifically to work in patchy, marginal coverage rather than only where signal is strong.
The first is automatic location sharing that fires the moment you dial, without you opening an app or turning anything on. The second is that your call isn’t actually limited to your own provider’s network. Neither of these replaces a Personal Locator Beacon in genuinely remote country, but they matter a great deal in the much more common situation: a trail with patchy coverage, not a trail with none.
Your phone shares your location automatically
Modern smartphones use a background capability called Advanced Mobile Location, or AML, that activates the instant your phone recognises you’ve dialled an emergency number. You don’t need an app open, a setting switched on, or even to know it exists. Any Android phone running Android 4.1 or later with Google Play Services, and any iPhone 6s or later running iOS 14.3 or later, has this built in.
Once triggered, AML pulls together whatever location data your phone can access, GPS, Wi-Fi, and mobile network information, and sends it as a text message directly to the emergency call centre, on top of the voice call itself. Reported accuracy is around 5 metres outdoors and 25 metres indoors, a considerable improvement on the older method of estimating a rough position from which mobile tower the call connected through.
For hikers this matters because it removes a step you’d otherwise have to get right under stress: describing your own location accurately. You should still give a verbal description of where you are and what’s happened, because AML supports the response, it doesn’t replace the conversation, but the coordinates are already on their way to the call taker as soon as you connect.
Your call isn’t limited to your own network
The second background feature is what’s sometimes called camp-on. If your own provider has no coverage where you are but another carrier’s signal reaches your location, your phone will automatically attempt the 000 call on that other network instead. Mobile carriers in Australia are required by law to carry emergency calls from competitors’ customers, so this isn’t a workaround, it’s a built-in part of how the emergency call system is designed to function.
This also works without a SIM card, with a disconnected or out-of-credit account, or on a locked phone. The one requirement that can’t be engineered around is that some carrier’s signal has to physically reach where you’re standing. If there’s genuinely no mobile coverage from any provider, camp-on has nothing to switch to, and that’s exactly the gap a Personal Locator Beacon is designed to cover instead.
Where this actually breaks down
I don’t think it’s honest to present any-network fallback as flawless, because it isn’t. A network upgrade issue affecting Optus in September 2025 caused a run of Triple Zero call failures linked to multiple deaths, and the review that followed found handset camp-on performance had never been systematically tested across the range of phones people actually carry. The regulator has since introduced mandatory testing requirements for how handsets behave when they need to switch networks to complete an emergency call, specifically because this had been an unregulated weak point.
The practical takeaway isn’t to distrust 000 on the trail. It’s that camp-on and AML are a safety net working in the background, not a guarantee, and they only function at all if there’s some mobile signal within reach in the first place. In places with no coverage from any carrier, none of this applies, and your emergency communication plan needs to be a device that doesn’t depend on a mobile network at all.
What this means for your safety planning
None of this changes what you should be carrying. If you’re heading into terrain where coverage is unreliable or absent, a PLB or satellite communicator is still what gets you found when a phone call can’t go through at all. What it does change is how you should think about a 000 call in the far more common in-between situation, patchy but not absent coverage, where a call might connect on a network you don’t even subscribe to and your location is already being sent before you’ve said a word.
If you do get through, stay on the line and describe your situation clearly regardless of whether you think your location has already been shared. Call takers work from what they can confirm, and search and rescue tasking depends on having as much confirmed information as possible, not just a set of coordinates.
