Measure underwater temperature, duration, and depth on Apple Watch Ultra
Apple Watch Ultra is a capable companion to accompany your ocean, lake, and pool activities. Use the Depth app 
to measure water temperature, underwater duration, and depth to 130 feet (40 meters).
WARNING: Underwater activities are risky. The Depth app is not a dive computer and does not provide decompression stop information, gas analysis, or other recreational scuba diving functionality. If you are using Apple Watch Ultra where the failure of the device could lead to death, personal injury, or severe environmental damage, always use a secondary depth gauge and timer/watch.
Depth app overview
The Depth app provides basic information that can be easily viewed during recreational underwater activities such as snorkeling, underwater pool swims, and shallow free-diving.
Important: The Depth app is not a substitute for a dive computer. Before going on a dive, be sure your Apple Watch Ultra is free of cracks or other damage.
On a single screen, Apple Watch Ultra shows the following:
Current time
Current depth and maximum depth
Time you’ve been underwater
Water temperature
Diving specifications | |
Maximum depth of operation | 130 feet (40 meters) Note: Apple Watch Ultra is designed to comply with EN 13319. Beyond 40 meters in depth, some functions may stop working or work intermittently. |
Depth when dive time counting starts and stops | 3 feet (1 meter) |
Underwater operating temperature range | 32° to 104° F (0° to 40° C) |
Accuracy of depth sensor | ± 1 meter |
Usability above sea level | Depth feature is functional above sea level. Apple Watch Ultra dynamically compensates for altitude before dives. |
Non-operational storage temperature | –4° to 113° F (–20° to 45° C) |
Inspection interval | Depth and dive time accuracy do not require rechecking at fixed intervals. However, if Apple Watch Ultra is damaged or malfunctions, contact Apple or an Apple Authorized Service Provider. |
Configure the Depth app
When you first set up Apple Watch Ultra, you choose how the Depth app opens—automatically when submerged, or manually, when you tap the app or press the Action button. To change that setting after you’ve set up your watch, follow these steps.
Open the Settings app
on your Apple Watch Ultra.Go to General > Auto-Launch.
Below When Submerged, turn Auto-Launch App on or off.
You can also open the Apple Watch app on your iPhone, tap My Watch, go to General > Auto-Launch, then, below When Submerged, turn Auto-Launch App on or off.
To choose depth and temperature units, tap Depth in the Settings app, then choose depth units (Feet or Meters) and water temperature units (Fahrenheit or Celsius).
You can also open the Apple Watch app on your iPhone, tap My Watch, then tap Depth.
Begin and end your dive
The Depth app begins operating when you submerge your Apple Watch Ultra. When submerged, the screen locks and Water Lock is turned on. In the Depth app, screen taps and Digital Crown presses don’t register. Third-party diving apps may allow you to interact with Apple Watch Ultra while underwater by turning the Digital Crown or pressing the Action button.
After you surface, press and hold the Digital Crown to turn off Water Lock, which clears water from the speaker.
You can also begin a dive in the Depth app by pressing the Action button. Open the Settings app on your Apple Watch Ultra, tap Action Button, tap Action, then choose Dive. When you’re ready to begin a dive, press the Action button.
Third-party dive apps
Apple Watch Ultra is compatible with third-party apps that can function as a dive computer for recreational scuba diving to 40 meters. Please refer to the third-party app documentation to understand how to use the app and the warnings associated with the app.
WARNING: Underwater activities are risky. To reduce the risk of serious or fatal injury, read and follow all instructions and warnings in this guide and those provided by any third-party dive apps you’re using, and when recreational scuba diving, always follow all guidelines associated with the certifications and training you have received.
WARNING: Always use a secondary depth gauge and timer/watch, as well as decompression tables.
WARNING: Apple Watch Ultra should only be used by trained divers for recreational dives of 130 feet (40 meters) or less. Always follow diving safety protocols and dive with a buddy. Check functionality regularly during a dive, and ascend safely if there is any apparent malfunction. There is always a risk of decompression sickness (DCS) with any dive. Seek immediate medical treatment if you think you may be experiencing DCS.