Apple watch ultra volume low

Hello Ianodp,

Thanks for posting in Apple Support Communities. We're happy to provide steps that may help with your Apple Watch Ultra.

Be sure to check the sound after each step:

1. Make sure your paired iPhone and Apple Watch are up to date: Update your iPhone or iPad - Apple Support and Update your Apple Watch - Apple Support
2. Check the microphone and speaker to see if anything is covering them. If there's debris, gently clear it away.
3. Check to see if water is in the microphone or speaker by placing the device, speaker side down, on a lint-free, microfiber cloth to see if any water drips out. Water in the port may degrade speaker or microphone performance until it completely evaporates. Then dry Apple Watch using a lint-free, microfiber cloth. Don't use heat, compressed air, or sprays, don't insert anything into the microphone or speaker ports, and don't shake the watch to remove water. Allowing Apple Watch to charge overnight may speed up evaporation. 
4. Restart the 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.
5. Unpair the Apple Watch from your iPhone, then pair them again: Unpair and erase your Apple Watch - Apple Support

If these steps don't resolve the issue, reach out to Apple Support directly: Contact - Official Apple Support

Take care.