Choosing a plan
How much mobile data do you need for a trip?
Build a data budget around your habits, rather than picking a number at random.
Use your own consumption as a starting point
Look at your recent mobile data use in your phone settings or your carrier account. Check which period the number covers: it may not be the current month. Divide that total by the number of days to get a rough daily baseline, then multiply it by the length of your trip.
For example, an observed average of 0.5 GB per day gives a starting estimate of 3.5 GB for seven days. This is an illustration, not a promise about what a particular app will consume.
Adjust for what will change abroad
A trip can change your habits. Think about video calls, uploading photos, watching video and using a laptop through your phone. If you expect more of these activities than usual, leave room above your baseline. If you plan to rely on Wi-Fi, still keep enough mobile data for the moments when it is unavailable.
Check the conditions, not just the GB
Before choosing, check whether you can buy more data, whether hotspot use is allowed and what happens when the allowance runs out. For a plan advertised as unlimited, read any fair-use or speed conditions. A clearly defined allowance can be easier to budget than a label whose restrictions you have not checked.