If I buy a model 6 watch and I am on att, will the same watch work when I switch to Verizon

Hi AxelIzzy57,

Thanks for participating in the Apple Support Communities. It sounds like you'd like to know if a series 6 Apple Watch activated with AT&T will work on the Verizon network, so we'd like to share a resource with you. Apple Watch GPS + Cellular goes into detail about which models work with which carriers in different regions.

Take care.

Yes it will but you have to setup a cellular plan;

Set up cellular on Apple Watch – Apple Support