iOS 18’s Messages via Satellite Feature Is Magic – TidBITS

Let me be blunt: if you have an iPhone 14 or later and live in the US or Canada, upgrade to iOS 18 now to get Messages via satellite. (The third-generation iPhone SE 3, released in 2022, lacks satellite support.) The satellite connectivity provided by the last three generations of iPhones should be part of everyone’s disaster preparedness, just as people used to carry cell phones in their cars purely in case of emergency. Sure, cell connectivity is widespread, except when it’s not, and as those affected by Hurricane Helene can report, it’s far from guaranteed in natural disasters. Roughly 75% of cell sites in affected areas of North Carolina were offline initially, primarily due to power outages and transport failures, and nearly two weeks later, 12% remain offline.

Apple doesn’t yet charge for its satellite services. The company notes that “Roadside Assistance, Emergency SOS, and Messages via satellite are included for free for two years with the activation of any iPhone 14 or later model.” However, Apple already extended that time frame for an additional year for iPhone 14 owners (see “Apple Extends Free Emergency SOS via Satellite for iPhone 14 Users for Another Year,” 15 November 2023). We’ll see what happens in November 2025.

Messages via satellite currently works only in the US and Canada, Roadside Assistance is available only in the US and UK, and you can use Emergency SOS in a handful of European countries plus Australia, Canada, Japan, and New Zealand.

A Brief History of iPhone Satellite Communications

Two years ago, Apple introduced Emergency SOS via satellite with the iPhone 14 and iOS 16 (see “Testing Emergency SOS and Find My via Satellite,” 21 November 2022). Giving a consumer-level cell phone powers equivalent to an expensive, dedicated satellite phone with a pricey service plan was an impressive technological (and business) feat. The technology proved its effectiveness within the year (see “Emergency SOS via Satellite Saves Lives in Maui Fires,” 10 August 2023). Apple also added the non-emergency Find My via satellite, letting you update your coordinates (every 15 minutes) so they can be viewed by people with whom you had already shared your location. When iOS 17 came out, Apple expanded the service to help stranded motorists with Roadside Assistance via satellite (see “Five Unexpected Announcements from Apple’s Wonderlust Event,” 12 September 2023).

While it’s impossible to criticize a service that literally saves lives, Emergency SOS via satellite was just the start. I guessed wrong about what would come in iOS 17, but my conclusion to “Testing Emergency SOS and Find My via Satellite” was prescient with regard to iOS 18 allowing text messaging via satellite:

So Apple, how about this for a roadmap? … if the satellite system proves capable of handling the traffic, iOS 18 could also allow us to send short texts via satellite.

Apple has now done that, enabling anyone with an iPhone 14, iPhone 15, or iPhone 16 running iOS 18 to communicate using Messages even when there is no cellular or Wi-Fi connectivity. It’s easy to do, but since you may not be able to find dead zones as easily as I can, let me show you the process and share usage notes. I also recommend trying Apple’s Satellite Connection Demo by tapping the Satellite button in Control Center.

Using Messages via Satellite

The iPhone’s satellite connectivity activates only when there is no cellular or Wi-Fi service; Airplane Mode isn’t sufficient. When you can use it, an SOS icon appears in the upper right corner of the screen, sometimes along with a satellite icon. I often find myself in SOS mode, but for this test, I biked 8 miles to a spot in the nearby town of Brooktondale that has no cell coverage. Imagine me standing next to my bike alongside a rural road on a fall day in upstate New York, holding my iPhone to the sky and rotating every few minutes.

Unlike cellular and Wi-Fi, satellite connectivity isn’t automatic. Activating the service requires a trip to the Settings app, where a Satellite option appears under Battery if you’re in the right circumstances. Alternatively, your first launch of Messages after entering SOS mode prompts you to enable the service; tapping the notification opens Settings > Satellite.

Apple offers a crisp explanation of satellite connectivity and how the connection process works. First, tap Use Messages via Satellite. Then, turn your iPhone to point at the satellite. Once you align your dot with the satellite image and see the green haze between the two, you’re connected. I’ll focus on Messages, but other buttons let you update your shared Find My location, start Roadside Assistance, or contact an emergency dispatcher using Emergency SOS. Although you can’t send your location using Messages via satellite, you can update Find My via satellite and message those who can see it to check where you are.

When you switch back to Messages, iPhone models with a Dynamic Island show a green dot and checkmark to indicate you’re connected; if it turns orange, you’ve lost connectivity and need to realign with the satellite. (I’m not sure how this looks on the iPhone 14 or iPhone 14 Plus, the only models with satellite support that lack the Dynamic Island.)

More interesting is how Messages informs you what’s possible within a conversation. The text field shows gray text reading either “iMessage • Satellite” or “Text Message • Satellite”. Apple’s documentation suggests four scenarios:

• iPhone users running iOS 18 or later can communicate via iMessage (top left, below).
• Non-iPhone users can receive and send messages via SMS (top right, below).
• iPhone users running iOS 17.6 or later can also receive and send via SMS (also top right, below).
• iPhone users running iOS 17.5 or earlier can receive via SMS but may not be able to reply.

Oddly, Tonya showed up as being allowed to use iMessage even though she’s still running iOS 17.6.1—I believe that’s because she upgraded one of her Macs to macOS 15 Sequoia. For those limited to SMS, Messages says, “Name may not be able to reply from devices where the software hasn’t been updated.” I received replies from all the people identified as such, so I’m unsure what Apple is warning about. If you don’t get a reply from someone who might be running an old version of iOS, that may be why.

The bottom two screenshots in the collection above show conversations that refused to allow satellite communications. The first is straightforward—group chats aren’t available via satellite, even if everyone is on iMessage. I get that—even if there isn’t a technical limitation, Apple presumably doesn’t want people overloading the system with chatty conversations.

The second is more obscure. Apple warns in its notes that iMessage won’t work for someone “if you haven’t sent them an iMessage recently,” but SMS should. That message appears in a conversation that hasn’t seen any traffic for six months. We should have been given the option to use SMS. On a subsequent test with TidBITS editor Glenn Fleishman, I was given the option to switch to SMS using his primary phone number. Oddly, the SMS messages I sent him disappeared from my iPhone once I had coverage again, even though they remained visible on Messages on both our Macs.

You may be able to force a switch to SMS in iOS 18 by going to Settings > Apps > Messages and making sure that Send as Text Message is available; you may also have to disable iMessage in the same spot. When I was back in cellular coverage, I could continue the conversation just fine, and it worked on a subsequent test. Add this to the weird prep list for going off the grid: send iMessages to infrequent conversation partners you may want to contact!  (Glenn speculates that Apple’s satellites or ground stations cache a subset of the hundreds of millions of security elements it creates for secure iMessage conversations and purges them over time when not in use.)

The primary functional difference between iMessage and text message conversations via satellite is the character count limitation. Satellite-based iMessage limits you to 500 characters; text messages are restricted to 140 characters, a limit inherent in SMS. Those restrictions are hard and fast—exceeding the specified number disables the send button. (Messages normally sidesteps the character count issue with regular SMS and MMS by sending multiple messages.) iMessage conversations via satellite are also end-to-end encrypted; SMS conversations are not.

Regardless of your connection type, you cannot send pictures, videos, audio messages, stickers, location, or anything else under the + button to the left of the text field. Emoji work fine, as do tapbacks. Despite not having an Internet connection, I was pleasantly surprised to be able to dictate my messages instead of tapping them out one letter at a time, like an animal.

Of course, messages are sent slowly, with send times sometimes reaching as high as 30 to 60 seconds, depending on the iPhone’s satellite connection. As you can see below, a blue or green fill bar appears at the top of the conversation while the message is sending. You can switch to other conversations or apps while it’s being sent. If you lose the satellite link, Messages will keep trying until you reconnect.

To receive replies, you must stay connected to the satellite. As long as that’s the case, conversations flow naturally. During testing, I exchanged messages with four people. Your iMessage correspondents are informed they’re communicating with you via satellite and must tap Send via Satellite for the first message, as my podcast friend Allison Sheridan did below.

My tests weren’t entirely successful, with my satellite messages to Tonya never arriving, although my iPhone shows them being sent via iMessage. We eventually discovered that they did arrive, but only on a little-used Mac that she had upgraded to Sequoia. I suspect that when she installs iOS 18 on her iPhone, satellite messages will appear there, too.

Apple doesn’t let arbitrary people, contacts or otherwise, message you before you connect to the satellite unless you’ve added them as an emergency contact or they are a member of your Family Sharing group. People in those two categories can message you via SMS while you’re offline, and their texts are delivered as soon as you connect to the satellite. (You can prepare for being otherwise unreachable by adding the current people you most need to remain in touch with to your emergency contacts.)

Messages shows these contacts a message when you’re off the grid and potentially reachable via satellite. Since they’ll likely be iMessage users, it’s unclear whether they need to disable iMessage (as explained above) to send you an SMS instead of an iMessage or if their iPhone will prompt them to resend as a text message when the iMessage isn’t delivered. Apple explains, “You won’t receive iMessages until your emergency contact or family member returns to the conversation and taps Send via Satellite underneath their message bubble.” My takeaway is that you shouldn’t assume any incoming messages will work until you’ve triggered your end of the conversation.

Maintaining your satellite connection may require no intervention for several minutes, but satellites move quickly, so you must rotate periodically to keep one in view. Also, satellites regularly fall below the horizon in any direction, so you may need to turn around to connect to a new one. The system is smart enough to tell you when the next satellite will be in range, with a countdown in minutes. Since I was just testing the system and wasn’t in distress, I found following the satellites around kind of fun.

When you’re done, just put your iPhone away to break the connection.

Although it comes with some weird caveats and footnotes, Messages via satellite worked sufficiently well in my testing that I have no qualms recommending it. I don’t expect to need it regularly, but I spend enough time in areas with weak cell service—largely on the trails and rural roads around Ithaca—to use it every month or two. I don’t want to oversell it as a life-saving feature—Emergency SOS via satellite ticked that box two years ago. Yet Messages via satellite will still make life easier and less stressful for millions of people. I’ll be able to communicate more readily while volunteering at trail races, and I can bike long distances knowing I can easily text for help if I blow a tire. Plus, while upstate New York isn’t usually plagued by hurricanes, tornadoes, floods, and other natural disasters that can disrupt the cell network, it could prove helpful during extreme weather events.

Ultimately, it’s not just about staying connected; it’s about being prepared for whatever life might throw your way. Messages via satellite provides essential connectivity that lets you reach out for help or comfort wherever you find yourself, whether you’re hiking in remote areas, traveling through cellular dead zones, or facing a natural disaster that has knocked out local infrastructure. If you’re still on the fence about upgrading to iOS 18, consider this a nudge.