Buy Ubigi if you want the best price on real data: $16.50 for 10GB on NTT docomo, Japan's widest network. Buy Airalo if you value the slicker app and you already use it in other countries — its 10GB Moshi Moshi plan costs $20 on SoftBank/KDDI. There is no wrong answer, because every travel eSIM in Japan is reselling the same three excellent networks. The differences are price per GB, top-up convenience and tethering rules. That's the whole comparison; the receipts follow.
The short answer
For a one-to-two-week trip with normal usage, buy a 10GB plan and stop thinking about it. At 1–2GB a day of maps, translation, photos and messaging, 10GB covers most 10-day trips with margin; heavy uploaders should size up to 20GB rather than unlimited. Both providers let you top up from the app in minutes if you misjudge — running dry in Japan costs you a coffee's worth of money, not a crisis.
Price table 2026
| Plan | Airalo (Moshi Moshi) | Ubigi |
|---|---|---|
| 10GB / 7 days | — | $14.00 |
| 10GB / 30 days | $20.00 | $16.50 |
| ≈20GB / 30 days | ≈$25.00 | similar tier available |
| Unlimited / 7 days | shorter unlimited variants | $25.00 |
| Unlimited / 30 days | — | $66.00 |
Per gigabyte on the standard 10GB/30-day plan: Ubigi $1.65, Airalo $2.00. Airalo's strength is the catalog around the price — frequent discount codes, loyalty credit, and one app that handles every country you'll ever visit. If you travel twice a year, that ecosystem is worth a few dollars; if Japan is the trip, Ubigi's sticker price wins.
Network and speed reality
Ubigi rides NTT docomo — the network with Japan's deepest rural and mountain coverage, which matters if your itinerary includes Hakone back roads, Kyushu valleys or ski country. Airalo's Moshi Moshi plans use SoftBank and KDDI, both excellent across every city and train corridor a first-timer touches. All three carriers deliver 5G in the metros. The honest caveat for every travel eSIM: as a reseller customer you can be deprioritized versus native subscribers in extreme congestion — think New Year's Eve at Shibuya Crossing, not a normal Tuesday. For navigation and uploads, you will not notice.
Setup: which is easier
Install either at home, days before flying — it's a five-minute job on hotel-quality wifi instead of airport floor wifi. Both deliver instantly: buy, scan or one-tap install, and the plan sits dormant until it first connects to a Japanese network. Airalo's app is the more polished of the two; Ubigi's does everything that matters, including top-ups onto the same eSIM profile so you never re-install. Either way, keep your home SIM active for SMS codes and turn off its data roaming — the eSIM handles data only.
When unlimited actually makes sense
Run the math on your real habits. Unlimited earns its price in exactly three cases: you'll hotspot a laptop for work, you make hours of video calls, or you upload video daily. Ubigi's $25/7-day unlimited beats buying 20GB+ for a heavy one-week trip; the $66/30-day version only pays off for genuinely data-hungry month-long stays. Note the fair-use reality of every 'unlimited' travel plan: sustained extreme usage can be throttled. For everyone else, 10GB plus a free top-up button is the calmer, cheaper play.
Pocket wifi: when it still wins
A rented pocket wifi router still beats eSIMs in one scenario: three or more people (or devices) sharing one connection, splitting one daily fee. The trade is real — one more thing to charge, carry, and return at the airport, and if the group splits up, only one half has internet. Couples do better with two cheap eSIMs. Solo travelers shouldn't even consider it. If your trip involves laptop work from cafés, an unlimited eSIM with tethering replaces the router outright.
Frequently asked questions
eSIM or physical SIM?
eSIM, unless your phone can't. 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 stores for older or carrier-locked phones — expect to pay more for the same data.
Does tethering/hotspot work?
On the standard data plans from both providers, yes — Ubigi explicitly allows data sharing and Airalo's Japan data plans support hotspot use. Some unlimited plans restrict or throttle tethering under fair-use rules, so read the plan page if the laptop matters to you.
Buy before flying or after landing?
Before, always. The plan activates only when it first touches a Japanese network, so nothing is wasted — and you land with working maps for the airport-to-hotel run, which is precisely the moment you least want to hunt for wifi. See our booking timeline for where this fits in trip prep: install around D−5.
Will my phone support it?
Any iPhone from XS/XR onward and most recent Pixels, Galaxies and other flagships support eSIM — but the phone must be carrier-unlocked. Check before buying: both providers list compatible models, and both refund unused, uninstallable plans within their policy windows. US-bought iPhones 14 and later are eSIM-only, so this is already your default.
