Today I Learned
Japan, apparently, the SIM with a phone number is the one tourists keep regretting they didn't get
Tabelog reservations, GO taxis, konbini pickup, Mobile Suica — the Japan services that quietly require a Japanese phone number, and the SIMs that include one.
A short story before the explanation
A friend — let’s call her K — flew into Narita on a Tuesday for her first trip to Japan. Tech-savvy, prepared, had read every guide, installed an Airalo eSIM 24 hours before the flight, walked out of the airport with full 5G bars in 90 seconds. Textbook.
Then over the next four days:
- She tried to confirm her Tabelog reservation at a small kappo in Yotsuya. The restaurant texts to confirm the day before; her foreign number got nothing; they released the seat to the next person on the list. She found out at the door.
- She tried to install GO (the Japanese ride-hailing app) at 11pm in Roppongi, drunk, in the rain. The app demanded SMS verification to a JP number. She got into the wrong taxi line and overpaid by ¥3,500.
- She tried to register Mobile Suica on her iPhone for hands-free transit. The Japanese App Store flow asked for a JP number for SMS verification on the bank step. She gave up and kept tapping a physical Welcome Suica card.
- She got a notification that a parcel ordered to her hotel needed a Japanese-format SMS code at the konbini for pickup. The number was not hers.
By Thursday she walked into a Mobal sales point in Shibuya and bought a Voice Lite SIM. ¥3,300 for the SIM, ¥990 for the month, a real 080 number. Everything above unlocked instantly.
She told me later: “I’d have paid ¥10,000 to have known this on the plane.”
Why this happens — Japan’s SMS-first identity stack
In the US and EU, services that need to verify “you are a real human” mostly use email + phone, with phone optional or skippable. In Japan, SMS to a Japanese phone number is treated as a primary identity proof, the way a national ID number is in some countries. The number is harder to fake (carriers verify residency for postpaid plans) and easier to charge against (premium SMS), so a generation of Japanese consumer apps simply assumed everyone has one.
That assumption breaks for tourists in five common spots.
The five places a JP phone number quietly matters
1. Restaurant reservations (Tabelog, OpenTable, TableCheck)
Japan’s reservation ecosystem confirms bookings via SMS the day before the reservation. The English Tabelog flow asks for a phone number, accepts foreign numbers, and then silently fails to send the confirmation to non-JP carriers in roughly 30-50% of cases (provider-dependent). For a 3-month-out reservation at a hard-to-book counter, that’s painful.
OpenTable’s Japan listings work better — most go through TableCheck for confirmations and accept email. But the long tail of Tabelog-only restaurants is huge, and many of the best ones are on Tabelog.
2. Ride-hailing — GO, DiDi, S.Ride
Uber exists in Japan but is small (Tokyo only, mostly black-car). The actual taxi-hailing apps that locals use are GO (the merger of MOV and JapanTaxi, dominant) and DiDi. Both demand SMS verification to a JP number at sign-up. No JP number, no app, no rain-night taxi at 11pm.
3. Mobile Suica / Mobile PASMO registration
Adding a Suica or PASMO to Apple Wallet on a foreign Apple ID has gotten easier since 2024, but the Japanese-bank-card route still typically requires SMS verification to a JP number when you link a credit card. Most travelers fall back to a physical Welcome Suica or Tourist PASMO instead — which is fine, but you lose the convenience of phone-only transit.
4. Konbini pickup of online orders
If you order anything to your hotel from Amazon Japan or Rakuten with konbini pickup as the delivery method, the SMS code that authorizes pickup is sent to a JP number. Some merchants accept email; many don’t. If your hotel concierge can’t accept parcels, this is the only option, and you need a number.
5. Mid-trip sign-ups in general
The pattern repeats for any Japanese service you decide to try mid-trip — coin parking apps, izakaya queue apps (EPARK), bike share (HELLO CYCLING), sometimes the multilingual Tabelog flow itself. The first screen of the sign-up asks for SMS verification.
The honest counter-argument: when you don’t need one
If your trip is structured like:
- 5-7 days, mainly Tokyo + Kyoto / Osaka.
- Hotel reservations made before departure (Booking.com, hotel direct).
- Restaurants booked in advance through OpenTable / Pocket Concierge / hotel concierge.
- Transit on a Welcome Suica or Tourist PASMO.
- No package deliveries, no ride-hailing, no in-trip app sign-ups.
Then a data-only eSIM is genuinely enough. Don’t pay for what you won’t use. The sweet spot for that traveler is an Airalo Moshi Moshi 7-day plan at ~¥1,650 for 5GB — see the 3-way comparison for details.
The audience that gets burned is the “semi-flexible itinerary” traveler — someone who wants the freedom to book a same-day reservation, hail a taxi at midnight, or order a ramen kit to their hotel.
The cheapest way to add a JP number
If the data-only eSIM is the right shape for your trip but you want the phone number as insurance, the trick is:
- Keep your data-only eSIM as the primary data line.
- Add a Mobal Voice Lite SIM (¥3,300 SIM cost + ¥990/month) as a second physical SIM in your phone’s SIM tray. It includes a real 080/090 number, includes 500MB of data you’ll basically ignore, and gets you unlimited free incoming SMS — exactly the thing you need for Tabelog and GO verification.
- You now have two lines: Airalo for cheap data, Mobal for the JP number.
Total added cost: roughly ¥4,300 for a one-month trip. Compared to one missed restaurant reservation at a hard-to-book counter, the math is obvious.
For travelers who prefer one-line simplicity, the Mobal Voice+Data eSIM or SIM does both jobs in a single line.
The “I’ll figure it out at the airport” trap
The Mobal sales counters at Narita and Haneda are genuinely helpful and you can walk up and buy a SIM with phone number in 5 minutes — but the number is only useful if you have it before you book the reservation, not after the restaurant has already released your seat. The decision to add a phone number works best made on the plane, not after the fact.
If you’ve already landed and you’re hitting the wall, check the eSIM activation step-by-step guide for the on-arrival options.
Closing
Japan’s services run on a quiet assumption that everyone has a Japanese phone number. Most tourists never realize this until something they wanted to do silently doesn’t work — a confirmation that never arrives, an app that won’t sign them up, a parcel they can’t pick up. Apparently the data-only eSIM era hasn’t quite caught up to the SMS-first country, and the fix is small: ¥1,000-3,000/month buys you a number, and that number unlocks the Japan that locals actually live in.