SafetyStop
Developed by Divers, for Divers
Dive computer support
This page exists because a support matrix is a promise. A diver reads "supported", buys a computer, and finds out on a boat whether it was true. So this one says what has actually been tested on hardware, what has not, and what cannot work on an iPhone at all.
Four models have been tested on a real iPhone. Read the state column.
Dive computer import ships and works — but "tested" on this page means somebody held that exact model and watched the dives land on an iPhone, and so far that is the Shearwater Peregrine, the Shearwater Teric, the Shearwater Perdix AI and the Suunto EON Core. The rest of the Shearwater family is Should work, which is usually a plan rather than a promise — though not always, so read the note on your own row. The EON Core carries a caveat the other three do not: a volunteer read one, but the code that reads it is not in the App Store version yet, so a diver downloading SafetyStop today still cannot use it. The three remaining Suunto EON models are at that untested state on weaker evidence again — they share the EON Core's protocol and nothing more has been measured about them. Check your model below before deciding whether SafetyStop is the app for it.
The three states
| Tested | Read from this exact model, on a real iPhone, and the dives landed in the log correctly. Nothing gets this label on a datasheet or a protocol document alone. |
| Should work | The protocol is known and the computer talks Bluetooth Low Energy, so there is good reason to expect it to work — but nobody has held one and proven it on an iPhone. Treat this as a plan, not a promise, and read the note on your own row: the rows in this state do not all rest on the same amount of evidence. |
| Cannot work | Not a missing feature. iOS physically cannot talk to it. See why below — this is the column nobody else publishes. |
The matrix
| Computer | State | Notes |
|---|---|---|
| Shearwater Peregrine | Tested | Read on a real iPhone, and the dives were checked against Shearwater's own app — ten dives, the worst depth disagreement 0.16 ft. This is the model the import was built against. |
| Shearwater Teric | Tested | Read on a real iPhone and the dives landed correctly. The app knows the Teric by name, so it is parsed as the technical computer it is — a 150 m depth ceiling like the Perdix, not the 80 m one used for recreational models. |
| Shearwater Perdix AI | Tested | Read on a real iPhone, and the whole log imported correctly on the first attempt. Worth reading if yours has never imported into SafetyStop: older Perdix AI firmware refuses to answer the model-number question every download opens with, and that refusal used to end the import before a single dive was asked for. It is now tolerated, so if yours has never imported, update SafetyStop and try again. |
| Shearwater Perdix / Perdix 2 / Perdix 3 / Petrel 3 | Should work | Same family, same protocol, same transport, and the app knows these model names — a Perdix 3 advertisement has been captured from real hardware so that its name resolves to the right parser rather than to a similarly named one. This family's decoding path has now run on an iPhone too, because the Perdix AI above identifies itself as a plain Perdix and was read as one. But no dive has been read off any of these four models themselves, so the row stays here until one has. The Perdix 3 additionally needs a newer build of the library underneath, which SafetyStop now links. |
| Suunto EON Steel | Should work same protocol as the tested EON Core; not yet tested itself, and not in the App Store version yet |
The app knows this name, and reads it as the start of a longer advertisement, because the one EON anybody has ever watched advertise over Bluetooth announced its model name followed by a serial number. The protocol is the same open-source library's, and all four Suunto models on this page share one code path inside it — the code path that has now read an EON Core. What is missing is a diver holding this model, and that is the only reason this row is not where the EON Core's is. |
| Suunto EON Core | Tested tested on hardware by a volunteer, 25 September 2026; not in the App Store version yet |
This is the model the work was done for, and it is the one Suunto that has been read: a volunteer imported dives off an EON Core on an iPhone on 25 September 2026 and they landed in the log. Two things to weigh with that. It was a volunteer's report rather than a device held here, and no recording of the download was kept — so this family still has no permanent test fixture. And the code that reads it is in a test build, not in the App Store version, so downloading SafetyStop today will not get you this. |
| Suunto D5 | Should work same protocol as the tested EON Core; not yet tested itself, and not in the App Store version yet |
One unknown more than the two rows above it, and worth stating plainly: the Bluetooth service a D5 presents is not documented anywhere public. The app looks for the service a real EON Steel Black was reported using, and assumes the D5 does the same. So a D5 may well be recognised by name and then fail to connect at all. If that is what yours does, say so — that is the one measurement nobody has. |
| Suunto EON Steel Black | Should work same protocol as the tested EON Core; not yet tested itself, and not in the App Store version yet |
The computer this family's groundwork came from: it is the one somebody else reported reading over Bluetooth, which is where both the advertised-name pattern and the Bluetooth service the app looks for come from. That is a second-hand report about a different model, so this row rests on somebody else's measurement plus the EON Core's protocol, and nobody has read a Steel Black into SafetyStop. |
| Any computer that only connects by USB cable | Cannot work | An iPhone cannot open a USB serial port without Apple's MFi hardware certification. This is most of the dive computers ever made, including many current models. |
| Any computer that uses infrared (IrDA) | Cannot work | iPhones have no infrared port and never have. Common on older Suunto and Uwatec models. |
| Any computer that uses classic Bluetooth (not BLE) | Cannot work | iOS only allows apps to use Bluetooth Low Energy. Classic Bluetooth serial needs MFi certification, same as USB. |
| Everything else | Unknown | If your computer speaks Bluetooth Low Energy it may be reachable in principle. Rather than guess, email and say which model you have. That is genuinely useful — it decides what gets worked on next. |
Why iOS is the limit, not the app
Most dive computers were designed to talk to a desktop computer. The open-source library that understands their protocols — the same one behind Subsurface — supports roughly 200 models, and the large majority of them connect over USB, RS-232 serial, or infrared.
An iPhone will not do any of those. Opening a serial connection to accessory hardware requires Apple's MFi certification, which is a hardware licensing programme, not something an app can enable. Infrared does not exist on the device at all.
So the set of dive computers any iPhone app can read is Bluetooth Low Energy only, and it is much smaller than a desktop list. An app that published the desktop list and let you find out the hard way would be wrong in the worst direction, so this page does the opposite.
You can always log by hand
Every SafetyStop feature works without a dive computer. Depth, time, gas mix, gas planning, MOD and PPO₂, printable log book pages, and offline water identification for the whole United States. Computer import saves typing; it is not the price of entry.
How this page gets updated
When a model is read on an iPhone, its row changes and the date below changes with it. If a model turns out not to work after being listed as "should work", that row moves to Cannot work with the reason — it will not quietly disappear.
A model can be proven on the hardware and still not reach Tested, and that gap is not a technicality: the Shearwater Perdix AI sat one row short of it for most of a day with its whole log already imported somewhere else, and moved only once an iPhone had done it. That distinction is kept rather than rounded up, because "we are fairly sure" and "we watched it happen" are different promises to make to somebody standing on a boat.