When you’re settling into life in Japan, the essentials you need after electricity, water, and gas are -of course- the internet.
Water and gas companies are assigned based on where you live. And you can choose your electricity provider, but in reality, the prices don’t vary much between companies.
However, mobile internet is a different story.
Many of the mobile carriers handing out free tissues on the street or in malls are, frankly, overpriced. And as I mentioned in another article, not knowing the right information ends up costing you money. And mobile internet is a perfect example of that.
So in this article, I’ll walk you through the best SIM card options available right now, based on a detailed price comparison chart.
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Mobile Plan Price Comparison
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First, here’s a breakdown of nearly all major mobile carriers in Japan and their pricing.
I know ... It's too complicated and hard to read. So I simplified everything below.
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The rows list the carriers, and the columns show the prices by data usage. For this comparison, I focused specifically on SIM cards that include voice calling.
In Japan, most mobile carriers offer two types of SIM cards. One supports data only, and another one supports both data and voice calls.
And since having a phone number is essentially required when living in Japan, I chose to compare the SIM card that allows voice calling.
Now, using this table as a reference, let’s get into how to choose the right mobile plan.
The Difference Between Expensive and Cheap SIMs
Before diving into recommendations, let's talk about why some SIM cards cost so much more than others.
For example, comparing docomo eximo with IIJmio.
The 10GB plan on eximo costs ¥7,315, while IIJmio charges only ¥1,400.
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Here’s why:
- Budget carriers don’t operate physical storefronts
- Budget Carriers lease network infrastructure from the legacy carriers
Budget Carriers Don’t Run Physical Stores
Carriers like IIJmio operate entirely online, without physical shops. This is why they can keep their costs down and offer their services at a lower price.
Budget Carriers Rent Infrastructure From Legacy Carriers
Budget SIM companies lease network access from Japan’s legacy carriers(au, SoftBank, and docomo). Technically, it relates to frequency bands, but for everyday use, you won’t notice any major differences so there’s nothing to worry about.
【Conclusion】Rakuten Mobile or IIJmio
So here’s the bottom line. If you’re unsure which mobile carrier to choose, you can safely pick Rakuten Mobile or IIJmio.
Here’s why:
- Rakuten Mobile：Best price for large or unlimited data
- IIJmio：Cheapest option with flexible data plans under 20GB
So which should you choose?
- If you use 20GB or less per month → go with IIJmio
- If you want to stop worrying about data limits → go with Rakuten Mobile
And both support eSIM. Let’s take a closer look at each option and what you need to sign up.
【Option①】Worry-Free Data Usage
If you want unlimited data without thinking about monthly limits, Rakuten Mobile is your best choice. As shown in the chart, Rakuten offers unlimited data for ¥3,278 per month, which is the cheapest option right now.
To sign up, you’ll need:
- Residence card
- Credit card or bank account
By the way, here’s my article on recommended bank accounts:
-
Best Bank Accounts for Foreigners in Japan.
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【Option②】20GB/Month Is Enough
If your monthly data usage stays under 20GB, IIJmio is the best option. Here’s the price list for IIJmio plans up to 25GB.
| Data Usage | Price |
| 2GB | ¥850 |
| 5GB | ¥950 |
| 10GB | ¥1,400 |
| 15GB | ¥1,800 |
| 25GB | ¥2,400 |
For reference, I have home Wi-Fi, so my mobile data rarely goes over 10GB, which is why I’m currently using IIJmio myself.
To sign up, you’ll need:
- Residence card
- Credit card
That covers the main recommendations for SIM cards.
Go with eSIM
Both Rakuten Mobile and IIJmio support eSIM. That means there’s no physical SIM card involved, you don’t have to wait for anything to arrive, and activation is much faster.
Before You Sign Up
Before submitting your application, make sure your device is compatible with the carrier.
Because some lesser-known models aren’t supported.
Rakuten is slightly trickier because compatibility is determined by software version.
For example, I use the Samsung S25 Ultra. It’s not listed on Rakuten’s compatibility page, but since it’s the successor to the Galaxy S23, it works without any issues.
And that wraps up my guide to choosing the right SIM card. I hope this helps make your life in Japan a little smoother.
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