Practical guides to calling abroad from the US, area codes, phone number formats, roaming and eSIMs.
Exact overlap windows from Eastern and Pacific time to London, Berlin, India, China, Japan and Sydney, plus the weeks in 2026 when daylight saving shifts them.
How to check that your phone can take a travel eSIM, which line should carry your data, and what happens to calls and texts on your US number while you're away.
What actually happens when your US line connects to a foreign network: which settings control data roaming, how Wi-Fi calling is billed, how to dial home, and why charges can show up weeks later.
