Is a travel eSIM safe to use?
Yes, an eSIM is at least as safe as a physical SIM: it cannot be stolen or swapped out of your phone, and the install goes through your phone's secure element. The real safety question is the provider; stick to established names and pay with a method that offers buyer protection.
Technically, eSIM improves on plastic SIMs: there is no card to steal, clone, or lose, the profile is bound to your device's secure hardware, and removing it requires your phone's passcode. The classic "SIM swap" attack at a carrier shop does not apply to a travel eSIM you bought online with no number attached.
The trust question shifts to the seller. A travel eSIM provider routes your traffic through partner networks, so choose companies with a track record: Saily comes from Nord Security (the NordVPN company), Airalo is the market's biggest name, and Ubigi is run by a subsidiary of NTT, one of the world's largest telecoms. Pay by credit card or PayPal so a dispute is possible, and download the app from the official store, not from a link in an ad.
Two practical safety habits: buy before you travel (airport Wi-Fi plus payment details is an avoidable combination), and remember that data-only eSIMs skip SMS, so keep your home SIM reachable for banking verification codes, with data roaming switched off.