beri am having iphone13 and plan to travel outside US where i will use esim, whether apple watch work connected to esim num

Ask your eSIM provider if they offer international roaming in the country concerned.

To be clear, a provisioned eSIM will work in any area of the world that a nanoSIM would work.

What MATTERS is if the calling plan supports international roaming.

(this has ALWAYS applied to ANY SIM)