How to Get a Mobal SIM Cheaper: What Actually Saves You Money

Most “promo code” pages for Japanese SIMs are a list of dead coupons. Mobal doesn’t really work that way — there’s rarely a code to paste at checkout, and the real savings are in how you set the thing up rather than in a discount you hunt for.

So this page does both. What’s actually on sale right now, and the choices that quietly cost or save you a few thousand yen over a stay.

Prices checked against Mobal’s site in August 2026, tax included. Promotions change, so confirm before you buy.

The short version

• There is a live promotion: 10% off the upfront SIM or eSIM price. No code needed — it’s applied on the site.
• The discount is on the one-off SIM price only, not your monthly plan. It’s worth ¥495, once.
• The bigger savings are elsewhere: activate mid-month for a pro-rated first month, start on a smaller data plan, and skip the add-ons you don’t need.
• Shipping is free either way, so choosing an eSIM over a physical SIM doesn’t save you money — it saves you waiting.

Is there a Mobal promo code?

Not in the usual sense. Mobal doesn’t run a coupon-code system where you paste something at checkout, so if a site is offering you “MOBAL20”, it’s making it up.

What Mobal runs instead is site-wide sales. At the time of writing there’s a summer promotion:

	Normal	On sale
SIM or eSIM, one-off	¥4,950	¥4,455
Voice-Only, monthly	¥1,430	¥1,430
Voice + Data, monthly	from ¥1,650	from ¥1,650

Read that table carefully, because it’s where most write-ups get it wrong. The 10% comes off the upfront price, not the monthly fee. You save ¥495, once. That’s real but it’s not the reason to buy, and if the sale has ended by the time you read this, you haven’t missed much.

There’s no activation fee and no termination fee at any time, sale or not — which is worth more than the sale, since Sakura Mobile charges ¥5,500 in activation fees alone.

Where the money actually goes

Three separate things, and people tend to only look at the first.

One-off: ¥4,950 for the SIM or eSIM (¥4,455 on sale). That’s it. No activation fee.

Monthly: ¥1,430 for voice-only, or a data plan:

Data	Monthly
Voice-only, no data	¥1,430
1GB	¥1,650
5GB	¥3,190
10GB	¥3,630
15GB	¥3,795
30GB	¥4,378
50GB	¥5,280

Usage, billed later: incoming calls and texts are free. Outgoing domestic calls are ¥44 a minute and texts ¥33 each. International calls go through a 0063 prefix at ¥65 a minute to most major countries. These land on your bill one to two months after you use them, which surprises people who’ve already cancelled.

Seven things that actually save money

1. Activate mid-month, not on the 1st. Your first month is pro-rated — you pay only for the days between activation and month end. Activate on the 15th and your first month is roughly half price. If you’re arriving near the end of a month and don’t need the line immediately, this is free money.

2. Start smaller than you think, then move up. 30GB is the popular pick, but you can change plans on the 1st of any month from your account. Starting at 10GB and moving to 30GB costs you nothing if you were wrong; starting at 30GB and never using it costs you ¥748 a month.

3. Let unused data roll over. Leftover data carries into the following month, so a light month subsidises a heavy one. It only rolls one month, so don’t bank on stockpiling.

4. Take the voice-only plan if you’re mostly on Wi-Fi. At ¥1,430 it’s the cheapest legitimate Japanese number a foreigner can hold. If you’re on Wi-Fi at home, at school and at work, and you only need a number that catches verification codes, this is the answer. Two caveats: no tethering, and no data means no WhatsApp or FaceTime when you’re out.

5. Don’t make outgoing calls. At ¥44 a minute, a few calls to a landlord and a bank add up faster than you’d expect. Use LINE or WhatsApp over data for anything that isn’t a real phone call to a Japanese business.

6. Skip voicemail unless you need it. It’s a ¥495 monthly add-on. Without it, unanswered calls simply end — which is fine for most people, and it saves ¥5,940 a year.

7. Don’t switch roaming on and off repeatedly. Roaming costs ¥5,995 each time you activate it, not per month. If you leave Japan and come back several times, that’s the single most expensive thing on your bill.

Two things that look like savings but aren’t

Choosing an eSIM to avoid shipping costs. Shipping is free. So is airport pickup. An eSIM saves you a wait, not money — and if your phone is a US-market iPhone 14 or later, or a Japanese-market iPhone 17, it’s not a choice at all, since those have no SIM tray.

Buying a data-only eSIM to save on the monthly fee. It is cheaper, and for a two-week trip it’s the right call. But a data-only line has no Japanese number, so no SMS codes — which closes off LINE registration, payment apps, Mobile Suica, ticketing sites and restaurant bookings. If you’re staying for months, you’ll end up buying a voice line anyway, having paid for both.

Keeping your number after you leave Japan

This is the one genuinely useful thing the voice-only plan does, and it’s worth spelling out the real cost.

If you go home but want to keep your Japanese number — for a bank, for app verification, for coming back next year — you can stay on voice-only at ¥1,430 a month and enable roaming. Incoming SMS stays free while roaming, so verification codes still reach you.

The catch is the ¥5,995 roaming activation fee, charged each time you turn it on. So the first year costs ¥1,430 × 12 + ¥5,995, or about ¥23,155. Worth it if the number is tied to a bank account you’re keeping. Not worth it for sentiment.

Also worth knowing before you plan around it: you can’t port an existing Japanese number into Mobal. If you already have a number with another carrier and want to keep it, this isn’t the route.

Is Mobal actually the cheapest?

For what it does, in the situation most readers are in, yes — but the honest answer has conditions attached.

Against Sakura Mobile, Mobal wins on day one: ¥4,950 with no activation fee versus ¥5,500 in activation fees, and an entry plan at ¥1,430 versus ¥3,278. Sakura has no equivalent to the voice-only tier. If you’re a student, ask Sakura about their activation-fee discount before deciding — it narrows the gap, though it doesn’t close it.

Against ahamo, LINEMO and the Japanese budget brands, Mobal loses on price and it isn’t close. Around ¥3,000 for 30GB is better than ¥4,378. But those brands need a residence card with your address printed on it, a Japanese bank account or credit card, and a signup flow in Japanese. Until you have all three — realistically several weeks after you land — they aren’t an option. Once you do, switching is the sensible move.

Against data-only eSIMs, Mobal is more expensive and always will be, because it’s selling something they don’t have.

So the fair summary: Mobal is the cheapest way to get a real Japanese phone number without a residence card. It is not the cheapest phone plan in Japan, and it doesn’t claim to be.

Common questions

Is there a Mobal student discount? We couldn’t find one advertised. The current 10% off the upfront price applies to everyone. Sakura Mobile does offer a student discount on its activation fee, so it’s worth asking both if you’re enrolled.

Do I need a code to get the discount? No. It’s applied automatically on the site during a promotion.

Can I really receive verification codes overseas for free? Yes, incoming SMS is free while roaming — but roaming itself costs ¥5,995 each time you enable it. The receiving is free; the switching on is not.

Is there a cancellation fee if I leave early? No. No minimum term and no termination fee. You can cancel from your account.

Why did I get billed a month after cancelling? Call and text charges arrive from the network one to two months late, so a final usage bill after you’ve cancelled is normal rather than an error.

What’s the cheapest possible Mobal setup? Voice-only at ¥1,430 a month, bought during a sale at ¥4,455, activated late in the month so the first month is pro-rated, with no voicemail and no roaming. Roughly ¥5,600 to get started and ¥1,430 a month after that.