Start with how your family will travel, not a fixed number of gigabytes per person. People who split up need independent connectivity; devices that stay together may be able to share a phone hotspot if the selected plan permits it.
When separate eSIMs make sense
Consider a separate compatible, unlocked phone and plan for each person who needs data while away from the group. A data-only eSIM is not a promise of a local phone number, SMS or ordinary voice calls. Agree how you will contact each other and arrange an offline meeting point if anyone loses connectivity.
When a shared hotspot can work
Check the specific plan's tethering policy before relying on one phone to connect tablets or laptops. The other devices need to remain within hotspot range, the host phone must stay powered, and everyone's usage draws from the host plan's allowance.
Compare the price and allowance of a suitable shared plan with separate plans for the same trip length. Streaming on several devices may use the allowance quickly; sharing is not automatically the cheapest option.
Prepare each device without starting validity too soon
Check each phone's exact model, regional variant and carrier-lock status. Read the installation and activation instructions for each purchased plan before setting it up early. Do not switch on every travel line at home just to test activation: validity triggers and coverage differ by plan.
Label each travel line and keep its instructions accessible. Store activation QR codes privately, and do not delete an installed profile unless support advises it; reinstallation may not be supported.
Reduce avoidable mobile data use
Download entertainment and maps over Wi-Fi where the apps support offline use. Review cellular permissions for streaming, app updates and cloud backups on each device. Base allowances on your family's own phone usage rather than a universal estimate.
On iPhone, Wi-Fi Assist can use cellular data when Wi-Fi is weak, so enabling it is not a data-saving step. Apple notes that it does not automatically switch to cellular while data roaming. Review Wi-Fi Assist and automatic SIM data switching separately; they are different settings.
Check every destination and travel day
For a multi-country holiday, compare each regional plan's explicit country list and validity with individual destination plans. Count arrival and departure days, and check the final price and currency before paying.