Prices and plan details checked 26 September 2026. Prices in USD.
Add up the days when you will need mobile data across the whole trip. Then multiply by a daily allowance that fits your own use. With a regional eSIM, you buy one balance for the route, so unused data from one country remains available in the next covered country.
Country count does not tell you how much data to buy. A three-country trip can need less data than a week spent uploading videos from one place. Time on mobile data and the way you use your phone matter more.
Start with your own phone’s data use
Check your phone’s mobile-data settings for a recent period when you used it in a similar way. Match the dates before treating the total as a daily figure. Think about what will change while travelling: more navigation, less home Wi-Fi, photo uploads or a laptop using your hotspot.
If you cannot estimate from your own use, compare a few budgets rather than treating one number as a universal allowance. The table below uses assumed daily amounts. It is a planning tool, not a measurement of typical travellers.
| Trip length | At 0.5 GB/day | At 1 GB/day | At 2 GB/day |
|---|---|---|---|
| 7 days | 3.5 GB | 7 GB | 14 GB |
| 10 days | 5 GB | 10 GB | 20 GB |
| 14 days | 7 GB | 14 GB | 28 GB |
| 21 days | 10.5 GB | 21 GB | 42 GB |
| 30 days | 15 GB | 30 GB | 60 GB |
For 14 days at 0.5 GB a day, the calculation is 7 GB. A 10 GB pack leaves 3 GB of room. At 1 GB a day, the same trip needs 14 GB, so a 20 GB pack or a smaller starting pack with a later top-up fits that budget. Check current top-up prices before deciding which costs less.
What our Japan customers used
Our Japan customer usage had an overall median of 4.7 GB per completed trip. For trips of a week or more with observed durations, daily use was around 0.7 GB. These are observations from Travelsim Asia customers in 2024 through mid-June 2026.
That gives some context for the Japan part of a trip. It does not establish a regional average or mean that 4.7 GB covers every trip length. Our Japan data guide explains the trip-length estimates and links to the underlying research. Budget the other stops using your expected use there.
A shared balance lets the daily use vary
Suppose you buy 10 GB for Japan and Korea, use 6 GB in Japan and arrive in Korea with 4 GB left. That is fine: a fixed regional plan does not divide the allowance into equal country portions or daily limits. You can use more on a travel day and less on a day with Wi-Fi.
With separate country plans, the balance stays with each country. Unused Japan data does not become Korea data. This can still cost less, but compare the amount needed at each stop rather than only the combined total.
Match the validity as well as the allowance
For the regional fixed plans covered by this guide, validity starts at the first connection in a covered destination. It keeps running while you move between countries, including days when you do not use the eSIM. A border crossing does not give you another 15 or 30 days.
If you live in a covered destination, connecting before departure starts the plan there. Install over Wi-Fi ahead of time if you wish, then enable the travel line when you are ready to start using it.
Pick a starting pack and check the balance
For routes covered by Asia 14 eSIM, 5 GB costs $10.99, 10 GB $19.99 and 20 GB $39.99, each for 30 days. Its 3 GB plan costs $6.99 for 15 days. Singapore and mainland China are excluded, so check the regional coverage guide before choosing on price.
You can top up the same eSIM from the dashboard linked in your email. The largest starting pack is not a ceiling on total trip usage. Check your remaining balance after the first few days; it gives you a better basis for the rest of the trip than guessing once before departure.
If your budget is several gigabytes every day, compare the full cost of larger fixed allowances and top-ups with unlimited alternatives. Read the full-speed allowance, reduced speed and hotspot rules. A competitor may offer a lower total for that pattern; the word “unlimited” alone does not tell you which deal is better.
Sources and related guides
Asia 14 eSIM; Japan customer usage and data guide; regional versus separate-plan comparison. The daily-budget table is calculated from stated assumptions, not from a regional usage study.