eSIM coverage for travelers is now genuinely good: global travel eSIM platforms sell plans for nearly every country, installable entirely online, and in many destinations the local carriers themselves offer tourist eSIMs through their websites or apps, which usually beat the global platforms on price and often include a local number.
The smoothest sequence is to buy and install before you travel, while you still have reliable wifi: purchase online, scan the QR code or use the provider's app to install the profile, and leave the line switched off until landing. Then you activate on arrival with one toggle and have data at the baggage belt. Installing on arrival works too but depends on airport wifi, which is an unnecessary gamble. Note that most travel eSIM plans start their validity clock at first activation or first connection, so read that detail.