EN
Saily
20 GB · 30 days
$24.99$1.25/GB
See this planBest eSIM for Japan for 21 Days (2026)
Choosing an eSIM for 21 days is mostly about validity and volume. With at least 11 GB over 21 days, the cheapest option we found is Saily at $24.99, and Saily scores best overall.
Updated September 24, 2026Prices checked September 24, 2026
We may earn a commission if you buy through our links, at no extra cost to you. It never changes the computed ranking. Affiliate disclosure
At a glance
Yesim
Unlimited · 21 days
$52.32
See this planSaily
20 GB · 30 days
$24.99$1.25/GB
See this planPlans compared for this trip
Plan shown: the cheapest plan of each provider that covers at least 21 days and 11 GB. Tap a column header to sort.
| Provider | Data | Validity | Price | Price/GB | Japanese network | 5G | Hotspot | Score | CTA |
|---|---|---|---|---|---|---|---|---|---|
| Saily | 20 GB | 30 days | $24.99 | $1.25/GB | KDDI/SoftBank | Yes | Yes | 9.8 | View plan |
| Airalo | 20 GB | 30 days | $25.00 | $1.25/GB | SoftBank/KDDI | Yes | Not stated | 9.2 | View plan |
| Yesim | 20 GB | 30 days | $29.76 | $1.49/GB | KDDI | Yes | Yes | 8.5 | View plan |
| Holafly | Unlimited | 30 days | $73.90 | — | KDDI/SoftBank | Yes | Yes | 6.4 | View plan |
| Drimsim | 15 GB | Pay as you go | $186.68 | $12.45/GB | Not published | Not stated | Not stated | 3.2 | View plan |
Detailed ranking
- 1
Saily
Plan for this page: 20 GB · 30 days
9.8/10- Price
- $24.99
- Price/GB
- $1.25/GB
- Networks
- KDDI, SoftBank
- Hotspot
- Yes
Pros
- Lowest price on this page
- Lowest price per GB on this page
- Unlimited plan available for Japan
Cons
- Data only, no phone number
- 2
Airalo
Plan for this page: 20 GB · 30 days
9.2/10- Price
- $25.00
- Price/GB
- $1.25/GB
- Networks
- SoftBank, KDDI
- Hotspot
- Not stated
Pros
- Unlimited plan available for Japan
- Two or more Japanese networks published
- Top-up without a new eSIM
Cons
- Data only, no phone number
- Hotspot policy not stated
- 3
Yesim
Plan for this page: 20 GB · 30 days
8.5/10- Price
- $29.76
- Price/GB
- $1.49/GB
- Networks
- KDDI
- Hotspot
- Yes
Pros
- Unlimited plan available for Japan
- Hotspot allowed
- 5G announced
Cons
- Data only, no phone number
- 4
Holafly
Plan for this page: Unlimited · 30 days
6.4/10- Price
- $73.90
- Price/GB
- —
- Networks
- KDDI, SoftBank
- Hotspot
- Yes
Pros
- Unlimited plan available for Japan
- Hotspot allowed
- Two or more Japanese networks published
Cons
- Data only, no phone number
- 5
Drimsim
Plan for this page: 15 GB · Pay as you go
3.2/10- Price
- $186.68
- Price/GB
- $12.45/GB
- Networks
- Not published
- Hotspot
- Not stated
Pros
- Wide choice of plan sizes
- Dedicated app
Cons
- No unlimited plan for Japan
- Pricier than the page average
What matters here
A 21 days trip is long enough for data use to drift upwards: more photos, video calls home, maybe some remote work. With the assumption used on this site the minimum is about 11 GB, but heavy users should check the estimator below before buying.
On longer stays unlimited plans become more attractive, because the price per day falls with the length. Yesim currently offers the cheapest unlimited plan lasting the whole trip, at $52.32. Check whether a daily fair-use limit applies.
Some providers let you top up the same eSIM instead of buying a new one, which is handy if you run out before the end. The provider reviews linked below say which ones publish a top-up option.
Every price on this page is the one published for Japan on the date shown at the top, in US dollars as the provider displays it; the final amount is the one shown at the provider’s checkout.
Guides on this site
How much data do you need?
Pick your trip length and how you use your phone. The assumptions are visible and editable.
Install your eSIM in 4 steps
- 1
Buy the plan before you leave and keep the QR code or the app handy.
- 2
Install the eSIM at home on Wi-Fi. Most plans only start the validity period once the eSIM connects in Japan.
- 3
On landing, switch the eSIM on for mobile data and keep your home SIM for calls and texts if you need them.
- 4
Turn on data roaming for the eSIM line, then check that the phone shows a Japanese network.
Your phone must be carrier-unlocked and eSIM-compatible. Check this in your phone settings before you buy.
Frequently asked questions
How much data do I need for 21 days in Japan?
With this site’s assumptions a light user needs about 0.3 GB a day and a medium user about 0.8 GB. For 21 days the plans shown here carry at least 11 GB; use the estimator to adjust.
What is the cheapest eSIM for 21 days in Japan?
Among the plans that last at least 21 days and cover at least 11 GB, the cheapest is Saily at $24.99. Prices were checked on September 24, 2026.
Which eSIM is best for a 21 days trip?
On today’s published prices Saily ranks first for 21 days, at $24.99. The score weighs price, Japanese network, hotspot and options; the formula is explained under the ranking.
Are unlimited plans really unlimited?
Many unlimited plans apply a fair-use rule and slow the speed after a daily threshold. Read the plan conditions on the provider’s page; Yesim currently has the cheapest unlimited option here at $52.32.
When should I install the eSIM?
Install it at home on Wi-Fi a day or two before you fly, then switch it on for mobile data when you land. With most providers the validity only starts once the eSIM connects to a Japanese network.
eSIM or pocket Wi-Fi for this trip?
For one or two people with compatible phones, an eSIM is lighter and usually cheaper. A pocket Wi-Fi can suit a large group sharing one connection; our Pocket Wifi vs eSIM guide compares both.
How we rank
We compare the plans each provider publishes for Japan. We do not rank on personal testing or user reviews. For each provider we take the cheapest plan that covers the need of this page, then compute a score out of 10:
- Price (50%): cheapest plan on the page ÷ this plan’s price × 10.
- Japanese network (20%): 10 if two or more networks are published, 8 for one, 5 if unknown.
- Hotspot (15%): 10 if tethering is allowed, 0 if not, 5 if unknown.
- Options (15%): app, top-up and an unlimited plan for Japan (10 each if yes, 0 if no, 5 if unknown).
At equal score, providers we have a partner link with are listed first. Prices change often, so check the final price on the provider’s site.
Top pickSaily · $24.99See this plan