Rakuten Mobile × povo Dual SIM: The Complete Guide [2026 Updated]

What's a Dual SIM, anyway? A dual SIM phone lets you run two separate carrier lines on a single device — switching between them whenever you need to. This guide breaks down how pairing Rakuten Mobile (for heavy data use and free calls) with povo (au network as your backup) gives you one of the cheapest and most reliable setups you can put together in Japan.

What Is Dual SIM?

Running a dual SIM setup means you have two separate carrier connections on one smartphone. Here are the three main reasons people do it:

• Network backup: If your main carrier drops out — underground, out in the countryside, wherever — your backup line keeps you online
• Flexible usage: One device, two lines: handy for keeping work and personal separate
• Cost optimization: Lean on the cheaper line as your primary, and top up only when you actually need it

Why Rakuten Mobile + povo Is Such a Smart Pairing

Reason 1: The Cost Is Hard to Beat

On a light month, your total bill can come out to just ¥1,078 (Rakuten) + ¥0 (povo) — which undercuts a lot of single-carrier budget plans.

Reason 2: Get the Most Out of Rakuten

Rakuten Mobile gives you unlimited data once you're past 20 GB, all for a flat ¥3,278/month. Domestic calls through the Rakuten Link app are completely free, with no cap on call time.

Reason 3: Patch Rakuten's Coverage Gaps with au

povo (from KDDI/au) runs on the au network, which tends to shine in the spots where Rakuten can sometimes struggle — underground malls, busy train stations, mountainous areas, and thick-walled buildings.

povo works on a "base plan + topping" model: the base plan is ¥0/month, and you layer on data bundles (called "toppings") only when you need them. No monthly commitment required.

Monthly Cost Simulations

The sweet spot for most people: Use Rakuten Mobile as your main data line and keep povo sitting on standby for free coverage backup. Only buy povo data toppings when you genuinely need them.

Downsides and Things to Keep in Mind

• You'll need a dual SIM-compatible phone: Most modern smartphones handle it fine (iPhone XS or later, most current Android models). Just double-check your specs before diving in.
• Slightly higher battery drain: Two active radio signals do eat a bit more power. Turning off the povo SIM when you don't need it helps a lot.
• povo's 180-Day Rule: If 180 days go by without you either buying a paid topping or making a phone call worth ¥660 or more, povo can suspend or terminate your account. Pick up at least one small topping every 6 months to keep the line alive.

Tip: A popular hack is to grab povo's cheapest topping (¥220 for a 24-hour 1 GB pass) once every 5–6 months — that's enough to reset the 180-day clock.

How to Set Up Dual SIM

On iPhone

1. Insert your physical SIM (or set up your eSIM) for both carriers
2. Open Settings
3. Tap Cellular (or Mobile Data)
4. Under Cellular Data, pick which line handles data by default

On Android

1. Insert your SIM cards (or add eSIM)
2. Open Settings
3. Tap Network & Internet
4. Tap Mobile data and choose your preferred default data SIM

Recommendation: Set Rakuten Mobile as your default data line (since it has unlimited data), and set povo as your default call line — or flip it around depending on how you use your phone. You can always switch manually on the fly.