Start with the things you will actually do
List the jobs your phone needs to handle between arrival and departure: finding the accommodation, checking a booking, messaging a travel companion and looking up a route. Add photo uploads, video calls or laptop work separately. Two people taking the same flight can need very different allowances.
Use your own recent mobile usage as a starting point, rather than assuming maps or messages always use a fixed amount. As a planning example, 0.2 GB a day over three days is 0.6 GB. Adding a 25% buffer gives 0.75 GB. At an assumed 0.8 GB a day, the same trip would need 3 GB after that buffer. These are arithmetic examples, not tested app consumption rates. Our travel data budget guide explains how to replace the assumptions with your own numbers.
A worked Portugal example: three bills to compare
| Plan example | Validity | Total price | Price per GB |
|---|---|---|---|
| Portugal · 1 GB total | 30 days | €0.48 | €0.48 |
| Portugal · 3 GB total | 15 days | €0.76 | €0.25 |
| Portugal · 5 GB total | 20 days | €1.04 | €0.21 |
These are selected Stellar total-data examples, checked on . For each displayed allowance we selected the lowest listed EUR price with at least seven days of validity; equal prices favour longer validity. This is not a comparison of every provider or every Stellar plan. Price per GB uses the full purchased allowance and is rounded to two decimals. Confirm the current price, coverage and conditions in the app before paying.
The €0.48 example buys 1 GB total with 30 days of validity. It is not 1 GB each day. The 3 GB example has 15 days, while the 5 GB example has 20 days. All three cover a three-day itinerary on the calendar, provided you start them at the correct time.
These examples illustrate a buying decision, not a recommendation for every destination. A Japan, Turkey or US plan has its own price and conditions. For this destination, see Portugal plans and their dated details, then confirm the current offer in the Stellar eSIM app.
Cheap unused data is still an extra purchase
The selected 5 GB example works out at about €0.21 per purchased GB, compared with €0.48 for the 1 GB example. But moving to 5 GB adds €0.56 to the bill.
If you used only 0.75 GB and the rest expired unused, the effective cost per used GB would be about €0.64 for the small purchase and €1.39 for the larger one. That is a hypothetical outcome, not a forecast. It shows why a lower unit price alone does not decide the better purchase. On the other hand, running out halfway through the weekend can make the smaller allowance inconvenient, so keep a sensible buffer.
Check when the clock starts, even on a short trip
A plan valid for seven or thirty days can still suit a weekend; you do not have to use every available day. What matters is that the validity includes the dates when you need a connection and that the allowance fits your use.
The selected examples list their start rule as the first supported network connection. Follow the instructions supplied with your exact order, including any installation window. Do not assume that switching the line off pauses an already running validity period. Our plan selection checklist separates installation, activation and expiry.
Keep total allowances separate from daily limits
A daily high-speed allowance and a total-data bundle are different products. Before comparing their prices, write down how much data is available on each day, what happens after the daily limit, and whether unused data carries over. Do not multiply a daily number into an unrestricted trip total unless the conditions actually support that interpretation.
The table above contains total-data examples only. If most of your usage will be on one long sightseeing day, a fixed daily limit may matter differently from a shared trip allowance. Compare the terms alongside the full cost for all the days you need, rather than treating the word “unlimited” as a complete specification.
Make the purchase fit the trip
Download large files and supported offline content before leaving. Check photo backups and automatic updates. Apple’s Low Data Mode and the mobile-data controls on Pixel can reduce some background use, but they are not a promise that a small bundle cannot run out. If you will share data with a laptop, add that separately using our hotspot planning guide.
In Stellar eSIM, choose the destination, buy the plan that fits your budget and follow its setup instructions. Check remaining data during the weekend and read the conditions of any available top-up. For a trip continuing into Spain, use the Portugal and Spain comparison rather than buying a Portugal-only allowance for both stops.
Sources & further reading
Product information and device guidance used for this article. Check your selected plan and exact device before purchase or setup.
