Measure underwater temperature, duration, and depth on Apple Watch
Apple Watch Series 10 and Apple Watch Ultra models can track the water temperature, time, and depth during underwater activities such as snorkeling, underwater pool swims, and shallow free-diving.
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. In situations 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: When using the Depth app, do not exceed the following maximum depth limits:
Apple Watch Series 10: 6 meters (20 feet)
Apple Watch Ultra models: 40 meters (130 feet)
The Depth app is not a substitute for a dive computer. Before going on a dive, be sure your watch is free of cracks or other damage.
If you want to check that the depth gauge and seals on your Apple Watch are working properly, you can get a Depth and Water Seal Test from Apple.
On a single screen, the Depth app shows the following:
Current time
Current depth and maximum depth
Time you’ve been underwater
Water temperature
Diving specifications for Apple Watch Ultra models
Maximum depth of operation | 40 meters (130 feet) Note: Apple Watch Ultra models are 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 | 1 meter (3 feet) |
Underwater operating temperature range | 0 to 40 °C (32 to 104 °F) |
Accuracy of depth sensor | ±1 meter |
Usability above sea level | The Depth feature is functional above sea level and dynamically compensates for altitude before dives. |
Non-operational storage temperature | –20 to 45 °C (–4 to 113 °F) |
Inspection interval | Depth and dive time accuracy don’t require rechecking at fixed intervals. However, if Apple Watch is damaged or malfunctions, contact Apple or an Apple Authorized Service Provider. |
Begin and end your dive
Begin the dive with one of the following methods:
Manually: Before you go into the water, open the Depth app
.Action button: (available on Apple Watch Ultra models) If you’ve set the Action button to Dive), press the Action button to start the dive.
Automatically: If you turned on Auto-Launch, the Depth app starts tracking a dive when your depth exceeds 1 meter and you’re submerged for more than 5 seconds.
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, end the dive session and turn off Water Lock (which clears water from the speaker) with one of the following methods:
Manually: Press and hold the Digital Crown.
Action button: (available on Apple Watch Ultra models) If you’ve set the Action button to Dive, press the Action button to end the dive.
Automatically: The dive ends when Apple Watch has been out of the water for 10 minutes.
If you descend again within 10 minutes without ending the dive, your time underwater is added to the previous time you were submerged and is logged as a single dive.
WARNING: Don’t switch to a different diving app within 48 hours of your last dive. Different diving apps, including the Depth app, may not share dive data and thereby may miscalculate critical parameters like tissue load. Failure to follow the warning may result in decompression sickness.
Third-party dive apps
You can install a compatible third-party app that can function as a dive computer at depths of 6 meters or less for Apple Watch Series 10, and 40 meters or less for Apple Watch Ultra models. 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.
Magnets in all Apple Watch models can affect the accuracy of an external compass. If you’re using another compass during activities such as diving, hiking, or navigating, keep it separated from Apple Watch when reading the external compass.
WARNING: Apple Watch Ultra models 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.