Unable to downgrade my Apple Watch from watchOS 26

Your Apple Watch is still on watchOS 26. There’s only two ways to remove watchOS beta.

1. Contact Apple support by call or chat to set up a mail in service to have the repair center restore it to the current OS. This cannot be done in an Apple Store or by Apple an authorized service provider.
2. Wait for watchOS 26 to be publicly released and no longer in beta.

Apart from sending the watch to Apple, you can disable future Beta updates for watchOS and wait until Apple launches the final version.

To disable Beta updates for watchOS follow the steps below:

1. Open the Watch app on iPhone
2. In the My Watch tab(bottom) tap General.
3. Tap Software Update.
4. Tap Beta Updates and then turn it off.

M1 Mac mini, macOS 15.5;  Watch, series 10 GPS-only, watchOS 11.5; iPhone 16, iOS 18.5; TV 4th Gen, tvOS 18.5 HomePods, audioOS 18.5

As per these FAQ's from Apple, downgrading a Beta version of watchOS is not possible:

...

Always back up your iPhone, iPad or Mac before installing the beta. Since Apple TV, HomePod mini, and HomePod (2nd generation) data and purchases are stored in the cloud, there’s no need to back up your devices. To use a previously-released version of iOS, iPadOS, or macOS, you can restore your device from the backup that you created before installing the beta. Please note Apple Watch cannot be restored to previously-released OS versions once the beta is installed.

...

copied from: Apple Beta — FAQ

To be able to use your Apple Watch, you will have to install the iOS 26 Beta again and pair your watch after that.

Otherwise you will not be able to use your watch until stable versions of the official watchOS 26 and iOS 26 have been released.

It can be done by Apple if you send it in but the charge is CAD$500+ I just got off the phone with them.

REnsing wrote:

It can be done by Apple if you send it in but the charge is CAD$500+ I just got off the phone with them.

Or, you can buy a new watch! That would make sense for Apple warning users that they will not be able to remove the beta and should be enough to persuade them from even trying it unless they are willing to ride it out to the release version.

Também estou com o mesmo problema. Fiz a atualização do meu iPhone para o IOS 26. Automaticamente meu Apple Watch atualizou para o IOS 26 tb. Acontece que o meu iPhone começou a ter bugs, travando demais os apps e lentidão. Eu fiz o downgrade no IPhone, do 26 para o 18.5 e ficou ótimo novamente. Porém ao tentar resetar o Apple Watch, aparece mensagem de que ele precisa do IOS 26 para atualizar. Não sei o que fazer, alguém poderia me ajudar nesse caso? Pois estou sem atualizar e usar o Apple Watch.