Rakuten Mobile AU to Rakuten Mobile Demerit Complete Guide for Foreigners in Japan [2026 Guide]

Are you currently on au and thinking about switching to Rakuten Mobile? You’re not alone. Many foreign residents in Japan are considering the move — especially with Rakuten Mobile’s flat ¥3,278/month unlimited data plan looking very attractive compared to au’s higher-tier pricing.

But before you make the switch, it’s worth understanding the potential downsides. Switching carriers in Japan can feel like navigating a maze, especially if Japanese is not your first language. This guide is designed specifically for foreigners in Japan and walks you through the real demerits of switching from au to Rakuten Mobile — so you can make an informed decision without any surprises.

What Makes Rakuten Mobile Appealing for Foreign Residents?

Let’s start with why so many people are considering this switch in the first place.

Rakuten Mobile’s primary plan costs ¥3,278 per month (tax included) and includes unlimited data on the Rakuten network. There are no tiered data charges, no bill shock, and no hidden fees. For foreigners who use their phone heavily for maps, translation apps, social media, and video calls home, this kind of flat pricing is genuinely appealing.

Additionally, Rakuten Mobile offers a generous employee referral campaign. If you sign up using an employee referral link, you can receive:

14,000 Rakuten Points for MNP (switching from another carrier like au)
11,000 Rakuten Points for a brand new number signup

Compare this to the standard campaign, which offers 13,000 points for MNP — the referral route gives you 1,000 extra points on top. These points are delivered in 3 installments, starting 4 months after the month you first logged in via the referral link.

If you’d like more details on how the referral system works, check out this helpful resource: Rakuten Mobile Employee Referral Complete Guide for Foreigners in Japan [2026 Guide]

Now, with the benefits covered — let’s get honest about the drawbacks.

Key Demerits of Switching from AU to Rakuten Mobile

1. Network Coverage Is Still Not as Wide as AU

This is probably the most significant concern for anyone switching from au. Au (and its parent company KDDI) has spent decades building out one of Japan’s most comprehensive mobile networks. Rakuten Mobile, by contrast, is a newer entrant and while its network has expanded rapidly, coverage in rural areas, mountainous regions, and some basements or indoor spaces can still be noticeably weaker.

Rakuten Mobile does have a roaming agreement with au for areas outside its own network, but this roaming data is capped. If you travel frequently outside major cities for work or leisure, you may notice the difference.

Who is most affected: People living in rural Japan, or those who travel regularly to countryside areas.

Who is least affected: People living and working primarily in major urban centers like Tokyo, Osaka, Nagoya, or Fukuoka.

2. No Physical Customer Support in Your Native Language

Au has a well-established support infrastructure in Japan, including in-store staff who can sometimes assist in English or arrange translation services. Rakuten Mobile’s in-store support is improving, but for non-Japanese speakers, navigating technical issues or account problems can still be challenging.

If you rely heavily on in-store or phone support, this is something to factor in. Rakuten Mobile’s app-based management is quite intuitive, but when something goes wrong — a billing issue, a SIM problem, an account lock — having accessible support matters.

Practical tip: Many foreigners find that Rakuten Mobile’s online chat support (accessed via the My Rakuten Mobile app) is easier to use than making phone calls to au, especially with translation tools.

3. AU Carrier Billing and App Subscriptions May Be Disrupted

If you currently use au Kantan Kessai (au Easy Payment) — au’s carrier billing system — to pay for apps, games, or subscription services, those payments will stop working once you leave au. You’ll need to set up alternative payment methods for each service before or shortly after switching.

This is a commonly overlooked demerit, particularly for people who use carrier billing for:

App Store purchases
Subscription services tied to au’s ecosystem
Certain Japanese streaming or content platforms

Make sure you audit your subscriptions before starting the MNP process.

4. AU-Specific Benefits and Loyalty Perks Will Be Lost

Au has its own ecosystem of benefits — including au PAY, au WALLET points, discounts through au Smartpass, and bundled discounts with other KDDI services. If you’ve been accumulating these benefits over several years, switching means leaving that ecosystem behind.

Rakuten Mobile, of course, integrates with the Rakuten ecosystem — and if you already shop on Rakuten Ichiba, use Rakuten Pay, or hold a Rakuten Card, you may find that Rakuten’s ecosystem is actually more valuable to you. But if your daily spending is heavily integrated with au’s services, there will be an adjustment period.

5. iPhone and Device Compatibility Considerations

Rakuten Mobile operates on Band 3 (1.7 GHz) as its primary frequency for 4G LTE, along with 5G bands. Most modern iPhones and Android flagships support Rakuten Mobile without issue.

However, if you’re using an au-locked older device, it won’t work on Rakuten Mobile until you get it SIM-unlocked. Au can unlock devices for free if you meet certain conditions (such as having used the device for a qualifying period), but if your device is on installment payments, there may be restrictions.

Before switching: Confirm that your current device supports Rakuten Mobile’s network bands, or plan to purchase a new SIM-unlocked device.

6. Point Delivery Timeline Requires Patience

This is relevant specifically to the referral campaign bonus. The 14,000 Rakuten Points (for MNP via referral) are not delivered immediately — they arrive in 3 separate installments, beginning 4 months after the month you first logged in via the referral link.

This means if you switch in June, you won’t start seeing your points until around October. For some people this is fine; for others who were counting on those points quickly, it’s worth knowing upfront.

The total is still 14,000 points — it’s just spread out. Think of it as a bonus that arrives gradually rather than all at once.

7. The MNP (Number Transfer) Process Has Multiple Steps

Switching from au to Rakuten Mobile via MNP (Mobile Number Portability) involves several steps that can feel bureaucratic:

Obtain your MNP reservation number from au (valid for 15 days)
Apply for Rakuten Mobile using your referral link before the MNP number expires
Complete identity verification (passport accepted for foreign residents)
Activate your new SIM and confirm number transfer
Cancel your au contract (some steps may happen automatically, but confirm this)

The process is manageable but requires attention to timing. Missing a deadline or making an error in your personal information can delay the process or, in rare cases, result in issues with number portability.

Is Switching from AU to Rakuten Mobile Worth It for Foreigners?

After looking at these demerits honestly, the answer depends on your personal situation:

Factor	Favorable for Switch	Less Favorable for Switch
Location	Major urban areas	Rural or mountainous regions
Language support	Comfortable with app-based support	Needs in-person Japanese support
Device	Unlocked modern smartphone	Au-locked older device on installments
Ecosystems	Heavy Rakuten user	Heavy au/KDDI service user
Data usage	High usage (benefits from flat plan)	Low usage (may not need unlimited)

For many foreign residents in Japan — particularly those living in cities, already engaged with the Rakuten ecosystem, and comfortable using apps — the switch is genuinely worthwhile. The ¥3,278/month flat plan is hard to argue with, and the referral campaign bonus adds real value.

Understanding the Free Calling Features Before You Switch

One aspect of Rakuten Mobile that surprises many new users is its calling system. Unlike traditional carriers, Rakuten Mobile uses a dedicated app (Rakuten Link) for free unlimited calls within Japan. This is a significant perk but works differently from how you may be used to making calls on au.

For a thorough breakdown of how this works and what to expect, this guide is worth reading before you switch: Rakuten Mobile Free Call System Complete Guide for Foreigners in Japan [2026 Guide]

How to Switch from AU to Rakuten Mobile via Referral (Summary)

If after reviewing all the above you’ve decided to move forward, here’s a quick summary of the recommended flow:

Log in to the referral link first — this is what triggers your eligibility for the 14,000-point MNP bonus
Get your MNP reservation number from au (via the au website, app, or customer service)
Apply for Rakuten Mobile while your MNP number is still valid
Complete identity verification using your residence card (zairyu card) and passport
Activate your SIM and start using Rakuten Mobile
Receive your points in 3 installments starting 4 months after your referral login month

Note: Up to 5 lines per person can be registered under the referral campaign, so if you have family members also on au, they can all benefit from the same referral.

Final Thoughts

Switching from au to Rakuten Mobile is not a decision to make lightly — there are real trade-offs. Network coverage, device compatibility, loss of au ecosystem benefits, and the multi-step MNP process are all things worth thinking through carefully.

That said, for foreign residents who live in urban Japan and want a simple, affordable unlimited plan with a bonus rewards package, Rakuten Mobile is a strong option. The flat ¥3,278/month pricing, combined with up to 14,000 Rakuten Points via the employee referral campaign, makes it one of the more compelling switches available in 2026.

If you’re ready to explore the switch, using a referral link is simply the smarter way to sign up — you get 1,000 more points than the standard campaign with no extra effort required.

You can access the employee referral link here: https://r10.to/henTIE

Take your time, review the checklist above, and make the switch when you’re confident it’s the right fit for your situation.