What the Apple Watch can and can't do without an iPhone
Phone home
The Apple Watch is designed to work with an iPhone. It's a second screen for the phone. A companion. A little extension of your smartphone that lives on your wrist.
But that doesn't mean it turns into a useless hunk of plastic if you leave your iPhone at home. Or you want to go for a run without a smartphone in your pocket.
Here's what the device can and can't do when it's not connected to its big brother.
What it can do
Tell the timeThe Apple Watch will continue to be a watch, even if you leave your iPhone at home. Your phone, however, takes care of adjusting between time zones and keeping the time precisely accurate.
You'll also still get alarms, timers, a stopwatch, and any calendar events that have been synced to the watch.
Play music and podcastsThe Apple Watch has about 2GB of internal storage space for music. It doesn't have a headphone jack, though, so you'll need to shell out for a pair of Bluetooth earbuds.
It can also store your most recent photos from your iCloud library, but you'll need a connection with your phone to see your entire collection.
Track your healthThe Apple Watch will use its own sensors to track most of your health and fitness stats when you're away from your iPhone, including your heartbeat, steps taken, stairs climbed, and your stand-sit ratio.
All of that stuff will be synced to your health app when you next grab your iPhone.
The Apple Watch doesn't have a GPS, though, so your distance and speed won't be tracked unless your iPhone is with you.
Pay for stuffThe Apple Watch has its own (secure) way to store your Apple Pay credentials, so you can use the watch to pay for stuff even if you've left your iPhone at home.
Get on planes, top up your Starbucks card, etcSimilarly, the Apple Watch doesn't need your iPhone around to use passbook data so you can use the wrist-hugging gizmo to board a plane, watch a movie, top up your Starbucks card, get in an event, or anything else that supports this tech.
Most internet tasksThe Apple Watch has its own wi-fi chip, and as long as it's on a known wi-fi network it can get online.
According to Yahoo! Tech reviewer David Pogue, "the watch can perform the most essential online functions even when your phone is completely dead, turned off, or absent."
"It can query Siri, for example, send and receive [messages], and send/receive drawings and tap patterns to other watch owners."
What it can't do
Third party appsDevelopers say that Watch apps not made by Apple must connect to the iPhone to do, well, just about anything. They might display themselves on the watch, but they're actually running on the phone.
That might change in future versions of the WatchKit SDK or later revisions of the Apple Watch itself. But for now, you'll need your phone to request an Uber or play Rules!.
Receive phone callsYour Apple Watch might be able to get online without an iPhone, but it can't make or receive phone calls, and presumably can't make or receive text messages to non-iPhone owners.
You're still going to need an iPhone in your pocket if you want to talk into your watch like you're Inspector Gadget.