Do I need to pay monthly for my aApple Watch connection?
Need to know monthly fee on my Apple Watch
Apple Watch Series 6, watchOS 9
That will depend entirely on the service provider you use with it. Apple does not itself charge a monthy fee for Apple watch usage.
Your mobile service provider may charge a feee on tom of your iPhone's service fee to add the watch to your service plan for Cellular service.
Contact your mobile service provider for information on there services fees and Apple Watch support.