Walking through the narrow streets of the 4th arrondissement, I noticed several small shops with a red diamond sign out front—a . These neighborhood kiosks sell everything from lottery tickets to SIM cards and top-up vouchers. It’s the most "local" way to do it, though you might need a little basic French to explain exactly what you need. The Modern Shortcut: eSIM

I asked for the Orange Holiday SIM Card . For about €40, it gave me 20GB of data, plus calls and texts throughout Europe—perfect since I was heading to Lyon next week.

You can often find plans for around €20, but keep an eye on those "hidden" international roaming charges if you leave the EU. The Old School Way: The Tabac

The plane touched down at Charles de Gaulle, and suddenly, my phone was a very expensive paperweight. I had the address of a tiny hotel in Le Marais, but without data, I was just a tourist with a paper map and a look of mild panic.