Just got a recent update on my watch 4. Everytime I disconnect from Bluetooth, like 5 minutes later my watch automatically turns Bluetooth back on and connects to my phone. It is so annoying when I do not want my Bluetooth on. I do not see a separate settings about this... Any thing about this!? Or a glitch
Maybe put your watch in airplane mode which will turn off Bluetooth. If you want to have a Wi-Fi connection, maybe watch will let you turn that on separately while in airplane mode. I don't have my watch 4 with me to check.