"How much does an eSIM cost to Japan?" is a question almost everyone asks before buying — but the cheapest number is not necessarily the best value for money. This article shows how to read prices correctly: what they depend on, how to calculate the true cost, and the hidden items that make a "cheap" package seem expensive.
The price difference between packages is almost always based on three factors:
Understanding these three axes, looking at the price difference between the two packages, you will immediately know why.
Don't compare two packages by absolute price, because they often differ in both GB and number of days. Let's convert to price per GB: divide the price by the number of GB. Illustrative example: 5GB package costs 100,000 VND = 20,000 VND/GB; 3GB package costs 75,000 VND = 25,000 VND/GB — the first package is cheaper per GB although the total cost is higher.
But there's a catch: price per GB only makes sense if you use it all. Buy a 20GB package "to make it cheaper per GB" and then only use 4GB for the whole trip, you're still overpaying. So estimate your actual needs first — see how to estimate how many GB are needed — and then compare the prices in the group of packages that suit you.
Many packages have "unlimited" recording but come with small conditions: only fast within a certain threshold (for example, 3GB of high speed per day), then squeeze the speed down to just enough for texting. "Unlimited capacity" is not synonymous with "unlimited speed".
Before paying for "unlimited", look for the fine print: What is the daily high speed threshold? If that's enough for you, a cheaper GB limited plan may be more reasonable.
To make it easier to imagine, here is the price of a 7-day "X GB high speed per day" package of some popular options for Japan, converted to VND at the exchange rate of ~26,300 VND/USD at the time of writing (original price in USD should be changed from time to time):
| 7-day package (daily) | Price | After the end of high speed |
|---|---|---|
| shibaSIM · 2GB/day | ~359,000 VND | still ~7 Mbps |
| shibaSIM · 3GB/day | ~459,000 VND | still ~7 Mbps |
| Airalo · "unlimited" (3GB/day) | ~710,000 VND | squeeze to ~1 Mbps |
| Holafly · unlimited | ~723,000 VND | ~1 Mbps, limited hotspot |
The specific number changes from time to time, but the big difference is in the last column: the package keeps ~7 Mbps after the high speed ends and can still be used normally, while many "unlimited" packages drop to a level that is only enough for texting.
Prices on the page are partial only. The following three things are not included in the numbers but directly affect the trip:
There is no one right number for all, because it depends on the number of days, capacity and exchange rate at the time of purchase. But the selection principle is simple:
You can see shibaSIM Japanese eSIM plans for current prices in VND; The package page has a tool to suggest capacity for how you plan to use it, so you don't have to guess "how many GB" yourself.
Depending on the number of days, capacity and exchange rate, the number changes from time to time — see current price on the package page. But note: the cheapest package is usually the package with the fewest GB and fewest days, which may not necessarily suit your needs. Choose according to your real needs and then optimize the price.
Worth it if you use it a lot and the daily high speed threshold is high enough. If you go basic, a limited GB plan is usually cheaper and still comfortable. Read the speed threshold carefully before deciding.
Depending on the supplier: some places calculate the term from the time of purchase, some places calculate it from the first activation. This is something you should ask clearly before paying, so as not to miss the deadline unfairly.
With shibaSIM, you pay in VND via VietQR transfer, no need for international card or foreign currency exchange.
"Reasonable price" is not the lowest price, but rather a package that meets your needs, covers enough days, and has support + refund in case of errors. Estimate your needs, calculate the price per GB in the appropriate package group, then carefully read the "unlimited" section and expiration date. See shibaSIM's Japanese eSIM plans — prices in VND, suggested capacity according to needs, retains Vietnamese number and supports Vietnamese during installation.
Detailed instructions on how to maintain a Vietnamese SIM to receive bank OTP codes and application messages when coming to Japan. Tips for using eSIM in parallel to help keep the connection smooth.
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