Apple watch over charging

Yes - the same applies to your iPhone 8 Plus, subject to following Apple's instructions and safety & handling guidelines, including:

• Charge and monitor the battery
• Keeping iPhone, iPad, and iPod touch within acceptable operating temperatures - Apple Support
• Important safety information

Hi

Apple advises that you can charge Apple Watch whenever you want. The battery on Apple watch cannot be overcharged and there is no need to let the battery discharge to any particular level first, nor any benefit to be gained from doing so:

Batteries - Why Lithium-ion? - Apple

Apple's tips for maximising battery life and battery lifespan on Apple Watch are detailed here:

Batteries - Maximizing Performance - Apple

You may find it most convenient to charge your Apple Watch nightly, overnight. The battery will not suffer any harm from regular charging. Charging will stop automatically when the battery is fully charged and start again if and when required due to ongoing battery usage. The battery will then be fully charged ready for the start of each day.

Be sure to follow Apple's safety and handling instructions (see the links below) and also note that:

• It is not possible to turn the watch off whilst it is on the charger and connected to power - this is normal.
• It is also normal for your watch, power adapter and charging cable to become warm when connected to power.

You may also find (the optional) Nightstand / Bedside Mode useful:

Use Nightstand mode on your Apple Watch - Apple Support

More information:

Apple Watch - Battery - Apple

Check your battery and charge your Apple Watch - Apple Support

Keep Apple Watch within acceptable operating temperatures - Apple Support

Important safety information

You're welcome! 🙂

I have addressed your separate question in your new thread:

Re: Apple Watch Language Issues