1.Start with your phone, not the plan
Before comparing prices, confirm two things about your device:
- Does your phone support eSIM? Ubigi's official guide gives a simple check: dial
*#06#— if an EID number appears, your device is eSIM-compatible. - Is your phone carrier-unlocked? Nomad's official guide states that carrier-locked devices cannot use third-party eSIM plans. If your phone is locked to your home carrier, no Japan eSIM in this article will work until it is unlocked.
If either check fails, solve that first.
2.Decide which shape of plan you need: fixed data or unlimited
Japan eSIMs come in two shapes, and the right one depends on how you use data.
Fixed-data plans give you a set amount (for example 5 GB) for a set number of days:
- Ubigi lists one-off fixed-data Japan plans from 1 GB for 3 days (US$3.50) up to 50 GB for 30 days (US$55), with steps in between such as 10 GB for 30 days (US$16.50). It also lists one-off unlimited options, from 8 days (US$25) to 30 days (US$65).
- Nomad lists fixed plans from 1 GB for 7 days (US$4) to 50 GB for 30 days (US$35); two of the listed prices were marked as sale prices, so they may not last.
- Saily's Japan page lists fixed plans from 1 GB for 7 days (US$3.99) to 20 GB for 30 days (US$24.99), plus an unlimited 15-day plan (US$48.99).
- Airalo's Japan fixed plans run from 1 GB for 3 days (US$4.00) to 20 GB for 30 days (US$25.00) — for example, 10 GB for 30 days is US$18.00. It also sells unlimited plans by the day (see below).
Unlimited plans charge by the day instead of the gigabyte:
- Holafly sells Japan as unlimited data only, priced by days: 3 days US$11.90, 7 days US$27.50, 30 days US$73.90.
- Nomad also lists unlimited plans (3 days US$11 to 10 days US$33). Its plan details state the fair-use shape: 2 GB per day at high speed, then speeds drop to 1 Mbps.
- Airalo's unlimited plans run from 3 days (US$11.50) to 30 days (US$69.00), and Saily's unlimited plan covers 15 days (US$48.99) with 5 GB per day at full speed, then up to 1 Mbps.
- "Unlimited" does not always mean "no conditions." Holafly's official Japan page did not state a numeric fair-use cap in the text we could read, so if you are a heavy user, check its help pages before buying.
A simple rule: if you mostly use maps, messaging, and translation, a fixed plan sized to your trip is usually the cheaper shape. If you work from your phone or stream video daily, look at unlimited — and read its fair-use conditions first.
3.Check when the clock starts
A "30-day plan" is only useful if the 30 days start when you think they do. Providers handle this differently:
- Nomad: you can buy and install in advance, but you must activate within 60 days of purchase — after that it activates automatically and the validity clock starts. The plan starts once it connects to the network at your destination.
- Holafly: install before you travel (through its app or a QR code) and switch the eSIM on when you arrive.
- Saily: its technical details state that the eSIM activates automatically when you arrive at your destination, and that you have up to 180 days to activate it.
- Airalo and Ubigi: we could not confirm the exact start trigger (installation, first connection, or arrival) from the official pages we read. Before buying, check the provider's help centre for "when does validity start" — it takes a minute and can save a plan.
4.Check tethering and calls before you rely on them
Two features people assume are included — and often are not:
- Tethering / hotspot: Holafly allows sharing, capped at 1 GB of shared data per day (so a 7-day plan includes 7 GB of sharable data in total). Nomad states hotspot is supported on its Japan page. For Airalo, Ubigi, and Saily we could not confirm tethering from the official pages we read.
- Voice calls: Holafly describes its Japan eSIM as data-only, and suggests keeping your WhatsApp number for calls and messages — there is no local voice number. For the other providers, whether the Japan plans include any voice number was not confirmed on the pages we read. If you need a Japanese phone number (some bookings and services ask for one), do not assume an eSIM data plan provides it.
5.Compare the total price for your number of days
Do not compare a 7-day price from one provider with a 30-day price from another. Fix your trip length first, then compare totals. Snapshot of official prices checked on 12 November 2026 (USD, dynamic — confirm before buying):
| Provider | Shape | Example prices (official, checked 2026-11-12) |
|---|---|---|
| Ubigi | Fixed data | 1 GB / 3 days $3.50 · 10 GB / 30 days $16.50 · 50 GB / 30 days $55 |
| Ubigi | Unlimited | 8 days $25 · 15 days $39 · 30 days $65 |
| Nomad | Fixed data | 1 GB / 7 days $4 · 10 GB / 30 days $16 (sale) · 50 GB / 30 days $35 |
| Nomad | Unlimited | 3 days $11 · 7 days $25 · 10 days $33 (2 GB/day high-speed, then 1 Mbps) |
| Holafly | Unlimited only | 3 days $11.90 · 7 days $27.50 · 30 days $73.90 |
| Saily | Fixed data | 1 GB / 7 days $3.99 · 10 GB / 30 days $17.99 · 20 GB / 30 days $24.99 |
| Saily | Unlimited | 15 days $48.99 (5 GB/day full speed, then up to 1 Mbps) |
| Airalo | Fixed data | 1 GB / 3 days $4.00 · 10 GB / 30 days $18.00 · 20 GB / 30 days $25.00 |
| Airalo | Unlimited | 3 days $11.50 · 7 days $26.50 · 30 days $69.00 |
Network note, for the providers that state it officially: Nomad lists KDDI au and SoftBank for Japan (its blog adds that fixed plans over 10 GB use KDDI au only); Airalo's package page lists SoftBank among its Japan networks; Saily's technical details list KDDI and SoftBank. We do not compare speeds or coverage quality — we have no measurements, and official pages do not provide comparable figures.
6.A 60-second pre-flight checklist
Before you pay for any Japan eSIM, run through this list:
- My phone shows an EID when I dial
*#06#(eSIM-compatible). - My phone is carrier-unlocked.
- I have chosen fixed data or unlimited — on purpose, not by default.
- The plan covers my full number of days in Japan.
- I know when the validity clock starts for this provider.
- I have checked tethering and voice against what I actually need.
- I have checked the provider's support channel (for example, Holafly lists email support and 24-hour chat; Airalo lists 24/7 multilingual support) in case something fails on arrival day.
- I have read the refund conditions on the official site. They differ a lot: Ubigi is the strictest (a purchased data plan generally cannot be refunded), while Holafly, Nomad, Airalo, and Saily mainly allow refunds before the eSIM is installed or the plan is activated — Nomad excludes its unlimited plans from refunds entirely. Read your provider's policy before buying, not after something goes wrong.