Before you buy a plan, check that your device supports eSIM. Most phones released since 2020 do, but there are exceptions, and a carrier-locked phone can't use the StaffTraveler eSIM at all.
The quickest check
Your phone can tell you directly.
iPhone: go to Settings > Mobile Service (or Cellular). If you see an option to add an eSIM, you're set.
Samsung: go to Settings > Connections > SIM Manager and look for Add eSIM.
Google Pixel: go to Settings > Network & Internet > SIMs and look for Download a SIM instead?
Any other Android: go to Settings > About Phone and tap Show EID. A number next to EID means your phone supports eSIM.
Which devices support eSIM
iPhone: iPhone XS and later. iPhone 14 and later sold in the United States have no SIM tray and are eSIM-only. The iPhone Air is eSIM-only everywhere.
iPad: cellular models of iPad Pro (3rd generation and later), iPad Air (3rd generation and later), iPad (7th generation and later), and iPad mini (5th generation and later). Wi-Fi-only iPads are not supported.
Samsung Galaxy: the S series from S20 onward, every Z Fold and Z Flip, and the A series from A35, A54, A55, and A56 onward.
Google Pixel: Pixel 2 and later. Pixel 10, 10 Pro, and 10 Pro XL sold in the United States are eSIM-only.
Motorola: Razr foldables, the Edge series, and selected Moto G models.
OnePlus: OnePlus 11 and later, and OnePlus Open.
Other brands: Huawei P40 and Mate 40 series, various Oppo and Xiaomi models, Sony Xperia 10 III Lite and later, Nothing Phone, and Fairphone 4 and later.
If your phone isn't listed, use the quick check above. It gives you a reliable answer for your exact model.
Exceptions to watch for
Some phones don't support eSIM even though the model normally does. This almost always comes down to where the phone was sold.
iPhone: iPhones bought in mainland China have no eSIM support, and neither do most from Hong Kong and Macao. The iPhone XS, SE (2020), 12 mini, and 13 mini are exceptions.
Samsung: devices sold in mainland China, Hong Kong, and Taiwan, most South Korean models, and the US versions of the Galaxy S20, S21, and Note 20 Ultra. FE models are excluded too, apart from the S23 FE and S24 FE.
Google Pixel: the Pixel 3 from Australia, Taiwan, or Japan, and the Pixel 3a bought in Southeast Asia or on Verizon.
Huawei: any Huawei bought in China, plus the P40 Pro+.
OnePlus: support depends on the region. Devices sold in China, Hong Kong, Macao, and India generally don't support it.
Carrier-locked phones
If your phone is locked to a carrier, you can't install the StaffTraveler eSIM, whatever the model. A locked phone only accepts SIMs from the carrier that locked it. Your carrier can usually unlock it once your contract is finished or the device is paid off.
No eSIM support?
If your phone can't use an eSIM, an eSIM.me adapter lets some Android phones use the StaffTraveler eSIM instead.