Is a travel eSIM cheaper than roaming?
Almost always, and usually dramatically. US carriers charge around $10 to $12 per day for international roaming passes; a 5 GB travel eSIM for Europe costs $15 to $20 once and lasts a month. On a two-week trip that is roughly $150 in day passes against under $20. Only for trips of a day or two can the carrier pass be worth its convenience.
Run the numbers on a typical case. A US traveler spending fourteen days in Italy with a major-carrier international day pass pays about $10 to $12 per day used: realistically $120 to $168 for the trip. The same traveler buying a 5 GB Europe eSIM from Saily or Nomad pays $16 to $17, and 5 GB covers two weeks of maps, messaging, photos, and normal browsing for most people. The gap is not small; it is roughly a factor of eight.
European travelers know a milder version: within the EU, "roam like at home" rules make roaming free across member states, so an eSIM only matters for them outside the EU. For Americans, Canadians, Australians, and anyone visiting from outside such a zone, the eSIM advantage applies almost everywhere they go.
When does carrier roaming still win? Trips of one or two days, where one $12 pass beats the minimum eSIM spend and zero setup beats any setup. Travelers who must keep their exact number reachable for regular calls also keep it simpler with carrier roaming, although the better answer is usually a cheap eSIM for data plus Wi-Fi calling on the home SIM. And corporate phones often roam on the company plan, where convenience is someone else’s invoice.