If the microphone or speaker isn’t working as expected on your Apple Watch
Try these steps if your Apple Watch microphone or speaker isn't working as expected. You can also use these steps if the sound is crackling, distorted, muffled or intermittent.
Update your Apple Watch and iPhone
Make sure your Apple Watch is up to date and your iPhone is up to date.
Clean your Apple Watch
Check the microphone (labelled 1 in the image) and speaker (labelled 2 in the image) to see if anything is obstructing them. If your Apple Watch has substances or debris visible in places such as the speaker ports, clean your Apple Watch. You can hold your Apple Watch under lightly running, warm, fresh water until it's clean. With Apple Watch Series 10, you can use a soft bristle brush to remove debris gently from the speaker ports. Don't use cleaning liquids, sprays or abrasives to clean your watch.
Apple Watch Ultra and later

Apple Watch Series 4 and later and Apple Watch SE

Apple Watch Series 3 (GPS + Cellular)

Apple Watch Series 2 and Series 3 (GPS)

Check for water and dry your watch
To check whether water is in the microphone or speaker port, place your Apple Watch microphone or speaker side down on a lint-free microfibre cloth. Water in the port may degrade speaker or microphone performance until it evaporates completely. Then dry your Apple Watch using a lint-free microfibre cloth. Don't use heat, compressed air or sprays, don't insert anything sharp into the microphone or speaker ports and don't shake Apple Watch to remove water. Allowing Apple Watch to charge overnight may speed up evaporation.
Restart your Apple Watch
Restart your Apple Watch by pressing and holding the side button, then slide to power off. Press and hold the side button again until the Apple logo appears.
Unpair your Apple Watch and then pair again
Unpair your Apple Watch and iPhone, then pair them again.
Get more help with the speaker
If you tried the above steps and your speaker still isn't working, follow these steps:
Check whether Silent Mode is on. To open Control Centre, press the side button (or, for watchOS 9 or earlier, touch and hold the bottom of the screen, then swipe up). If Silent Mode is on, turn it off.
Check whether Do Not Disturb is on. To open Control Centre, press the side button (or, for watchOS 9 or earlier, touch and hold the bottom of the screen, then swipe up). If Do Not Disturb is on, turn it off.
Adjust the sound. Open the Settings app, scroll down, then tap Sounds & Haptics. Tap the volume buttons under Ringtone and Alerts. You can also tap the slider once to select it, then rotate the Digital Crown to adjust the volume. The Apple Watch speaker will play audio at the volume selected.