Ubigi wins on price and on paper: $16.50 for 10GB over 30 days, riding all three major networks (KDDI, NTT docomo and SoftBank), and it tells you plainly when your plan starts — on arrival in Japan, never before. Airalo charges $18 for the same 10GB, runs on SoftBank and KDDI, and gives you the better app plus one account for every country you'll ever visit. Both prices were read off the providers' own plan pages on 19 October 2026. Below: every plan size, the specs that actually differ, and the install-timing question that costs travellers days of their plan.

The short answer

Buy Ubigi if Japan is the trip and price per gigabyte decides: $16.50 for 10GB, all three major networks, and an activation rule you cannot get wrong. Buy Airalo if you already have the app, want one account across countries, or want its 20GB/30-day plan at $25 — $1.25 per gigabyte, cheaper per gigabyte than any one-off plan Ubigi sells below 50GB. Neither is a mistake. They resell the same national networks; the gap is a few dollars, one carrier, and the app you prefer.

Airalo vs Ubigi: every plan size, October 2026

Ubigi is cheaper at the size most first-timers buy: 10GB/30 days at $16.50 against Airalo's $18, and 10GB/7 days at $14 against $17. Flip it in the 20GB range — Airalo's 20GB/30 days is $25, or $1.25 per gigabyte, while Ubigi's nearest tier is 25GB for $32. Ubigi's 50GB/30 days at $55 ($1.10 per gigabyte) is the cheapest rate on this page, for heavy users only. Airalo has the denser ladder: 5GB and 10GB in 7-, 15- and 30-day versions.

PlanAiralo (Moshi Moshi)Ubigi
1GB / 3 days$4.00$3.50
3GB (short validity)$7.50 / 3 days · $8.00 / 7 daysnot sold
5GB / 30 days$11.00not sold (5GB / 15 days: $10)
10GB / 7 days$17.00$14.00
10GB / 30 days$18.00$16.50
20–25GB / 30 days$25.00 (20GB)$32.00 (25GB)
50GB / 30 daysnot sold$55.00
Unlimited / about a week$26.50 (7 days)$25.00 (8 days)
Unlimited / 15 days$48.00$39.00
Unlimited / 30 days$69.00$65.00
List prices read off airalo.com and cellulardata.ubigi.com on 19 October 2026. Both providers run promo codes and seasonal discounts — treat these as the ceiling, not the floor.

The specs that actually differ

Price is the easy part. Four things change your trip: which carriers you get, whether hotspot is allowed, whether a top-up lands on the eSIM you already installed, and when the countdown starts. Ubigi publishes all four on the plan page itself. Airalo publishes tethering and top-up rules in its help centre and sets activation timing per package — first connection for Japan, but install-based on some other packages, which is exactly where people lose days.

SpecAiraloUbigi
Networks in JapanSoftBank + KDDIKDDI + NTT docomo + SoftBank (all three)
Tethering / hotspotAllowed — "as long as it is supported by your device and the network"Allowed — plan pages state "Data sharing allowed"
Top-upSame eSIM, from the My eSIMs tab, if the eSIM is rechargeableSame eSIM, in-app, no re-install
When validity startsJapan packages: first connection to a network in Japan (Activation Policy set per package)SmartStart — automatically on arrival in Japan
Shelf life before activationNot stated on the Japan plan pageExpires 6 months after purchase if never activated
ID / eKYC checkNone on the Japan plansNone on the Japan plans
Unlimited fair-use, published3GB a day at full speed, then 1 Mbps, on every Japan unlimited package8 days: 5GB a day, then 2 Mbps (resets every 24h) · 15 days: 30GB then 2 Mbps · 30 days: 60GB then 2 Mbps
Specs quoted from airalo.com (Japan package data and help centre) and Ubigi's Japan plan pages, 19 October 2026. Airalo sets the Activation Policy per package — check it on the package page before you install.

When should you install it — and when do the 30 days start?

For Ubigi, install whenever you like. Its Japan plans use SmartStart: the plan activates on arrival in a covered destination, "with the validity period starting from that moment". For Airalo it depends on the package, and the Japan ones are the easy kind. Airalo's help centre says most eSIMs activate when they connect to a supported network at the destination, some at installation. The Japan packages' Activation Policy reads: "The validity period starts when the eSIM connects to a mobile network in its coverage area."

That split is why the question keeps resurfacing on r/JapanTravelTips. If your plan is the connection type, installing at home two weeks early costs nothing and buys you working maps the moment the plane doors open — which is precisely when you want them, standing in an arrivals hall with a QR code to show and a train to find. If your plan is the install type, doing the same thing burns days off a 30-day plan before you've left the house.

The procedure that is safe for both: buy early, install early, and leave the eSIM line switched off in your phone's settings until you land. Installing a profile is not the same as enabling it. On arrival, turn the line on, point cellular data at it, and keep your home SIM active for SMS codes with its data roaming off. If you're on Airalo and the Activation Policy reads install-based, don't install until the day you fly.

Ubigi adds a second clock worth knowing about: an unactivated plan expires six months after purchase. Buying a Japan eSIM in January for a July trip is fine. Buying one in June for the following January is not.

What about Saily and Holafly?

Saily is the credible third option: $17.99 for 10GB/30 days on KDDI and SoftBank, hotspot allowed, 180 days to activate. It undercuts Airalo and loses to Ubigi. Holafly is a different product — for Japan it sells unlimited only, $11.90 for 3 days up to $73.90 for 30, and its hotspot is capped rather than unlimited. If you want a cheap 10GB plan, Holafly doesn't sell you one.

Saily's Japan ladder as listed on saily.com today: 1GB/7 days $3.99, 3GB/30 days $7.99, 5GB/30 days $10.99, 10GB/30 days $17.99, 20GB/30 days $24.99, and unlimited at $48.99 for 15 days, running 5GB a day at full speed before dropping to 1 Mbps. Hotspot is explicitly allowed on every tier. It is a fine choice if you already use it; it is not a reason to switch away from either provider above.

Holafly's Japan page lists $11.90 / 3 days, $20.50 / 5, $27.50 / 7, $36.50 / 10, $50.50 / 15 and $73.90 / 30, all unlimited, on KDDI and SoftBank. The tethering caveat is Holafly's own wording, not ours: its FAQ says "the hotspot feature is not unlimited to preserve network integrity" and points you at each destination's Technical Specs, and the Japan page frames sharing as 1GB a day. So the answer to "is Holafly's tethering unlimited?" is no, and you should check the number for Japan before you rely on it.

The honest summary for anyone hunting an Airalo alternative for Japan: Ubigi is the cheaper like-for-like swap, Saily is the closest match in look and feel, and Holafly is only an alternative if unlimited data is non-negotiable and you're travelling alone. For two people splitting one connection, two capped eSIMs beat one unlimited plan every time.

How much data do you actually need?

Most first-timers use 0.5–2GB a day: maps, translation, messaging, some photos, hotel wifi at night. That makes 10GB the sane default for a one-to-two-week trip, with the top-up button as your safety net. Only streaming on trains, daily video uploads or hotspotting a laptop push you into unlimited territory. We settled that decision properly in a separate piece rather than repeat it here.

The short version: every "unlimited" plan is really a fair-use plan, and a big capped plan often costs less than the unlimited one sitting beside it — Ubigi's 25GB/30 days is $32 against $65 for its unlimited month. If you're weighing unlimited against a large capped plan, our unlimited Japan eSIM guide has the crossover math, the throttle thresholds and the traveller profiles it actually suits.

Getting online the moment you land

Both providers activate on the same trigger you'll hit at the gate: your phone finding a Japanese network. That matters more than it sounds, because immigration and customs now run through Visit Japan Web, and you want that QR code loading without hunting for airport wifi. Add Visit Japan Web to your home screen before you fly — its official manual says it can then show the code offline — but a live data connection is the backup that turns a fifteen-minute fumble into a thirty-second scan. Check the entry rules first: most passports do not need a visa for Japan at all.

From there it's trains. Airport wifi at Narita and Haneda is free and workable, so an eSIM is not strictly required to reach your hotel — see every airport-to-Tokyo option ranked — but a working phone on the platform is the difference between confidently boarding the right limited express and asking a stranger. Budget-wise, data is a rounding error on a Japan trip: $16.50 against the ¥20,000–25,000 a day we budget per person for a first trip. Set up a Suica in your phone before you fly too, and the ticket gates open with the same device.

If you want that daily figure broken down properly rather than guessed at, we have the real per-day budget. The eSIM is the cheapest line on it, and the one that makes every other line easier to manage.

Pocket wifi: when it still wins

A rented pocket wifi router still beats eSIMs in one scenario: three or more people sharing a single connection and splitting one daily fee. The trade is real — one more device to charge, carry and return at the airport, and if the group splits up, only one half has internet. Couples do better with two capped eSIMs. Solo travellers shouldn't consider it. For laptop work from cafés, an unlimited eSIM with tethering replaces the router outright.

Frequently asked questions

When should I install the eSIM? Does the countdown start at install or first connection?

Ubigi: install any time. Its Japan plans use SmartStart and activate on arrival, with validity running from that moment — though an unactivated plan expires six months after purchase. Airalo: it depends on the package. Its Japan packages list a first-connection Activation Policy (checked 19 October 2026), but some other countries' packages start at installation, so check Additional Information > Activation Policy before you install. Safest habit for both: install at home, leave the line switched off, enable it after you land.

Does tethering / hotspot work?

On both, yes. Ubigi states "Data sharing allowed" on its Japan plan pages. Airalo's help centre says you can use your personal hotspot "as long as it is supported by your device and the network", with no country exception listed. Holafly is the one to watch: its own FAQ says the hotspot feature is not unlimited, and its Japan page frames sharing as 1GB a day. If the laptop is the point of the plan, that matters.

Can I top up, or do I have to buy a new eSIM?

Both let you top up the profile you already installed — no second QR code, no re-install. Ubigi tops up in-app, and its plan pages note you can do it once your allowance is consumed. Airalo shows a Top up button under My eSIMs for rechargeable eSIMs; if the button is missing, that package isn't rechargeable and you buy a fresh one. This is why running low in Japan costs you a coffee, not a crisis.

Do I need to show ID to buy a Japan eSIM?

No. Some destinations require identity verification before an eSIM will activate, and Airalo flags eKYC on those packages. Neither Airalo's nor Ubigi's Japan plans carried an ID or eKYC requirement when we checked on 19 October 2026. Buy with a card, get the QR code by email, done. Physical tourist SIMs bought at an airport counter can still ask for a passport.

eSIM or physical SIM?

eSIM, unless your phone can't take one. It's cheaper, installed from your sofa, and doesn't involve fishing a tray pin out of your bag at Narita. Physical tourist SIMs still exist at airport counters and electronics shops for older or carrier-locked handsets — expect to pay more for the same data, and expect a queue at the counter after a long-haul flight.

Will my phone support it?

Any iPhone from XS/XR onward and most recent Pixels, Galaxies and other flagships support eSIM — but the handset must be carrier-unlocked. Check before buying: both providers list compatible models, and both have refund policies for plans that were never installed. US-bought iPhone 14 and later are eSIM-only, so for most American readers this is already the default.