Last updated: Jan 9, 2026 (JST).

Rakuten Mobile's network has evolved dramatically from its early days of limited coverage, now reaching virtually all populated areas across Japan with steady 5G expansion and increasingly reliable service in previously challenging environments like subways, underground shopping complexes, and building interiors. This comprehensive guide shows you how to verify coverage at your specific address, understand what Rakuten's map actually means in real-world terms, decode the difference between "Rakuten area" and "partner coverage," and set realistic expectations for performance on trains, in buildings, and underground.

Current Coverage Snapshot

Rakuten Mobile's network has reached maturity with 99.9% population coverage as of December 2025, according to the official English site at network.mobile.rakuten.co.jp/en/. This milestone represents a remarkable achievement for a carrier that launched its network from scratch just a few years ago, competing against established carriers with decades of infrastructure development.

The 5G rollout has accelerated significantly throughout 2025, with Sub-6 mid-band 5G coverage expanding dramatically across multiple regions. The company reported year-over-year gains of up to 100% in parts of Kyushu and Okinawa, with Okinawa prefecture approximately doubling its 5G footprint. Other notable improvements include 110% increases in Kanto region 5G coverage and 40% expansion in Yamaguchi prefecture. These aren't incremental improvements—they represent substantial leaps in next-generation network availability.

The 700 MHz "platinum band" commercial service launch in June 2024 marked a turning point for Rakuten's indoor and rural coverage. Lower-frequency platinum band signals penetrate buildings, underground structures, and rural terrain far more effectively than the higher-frequency bands Rakuten initially deployed. This addresses what had been the network's most significant weakness—reliable connectivity inside steel-reinforced concrete buildings, subway stations, and countryside areas where higher frequencies struggle to reach.

Key numbers:

Population coverage: 99.9% as of Dec 2025
5G momentum: Up to 100% gains in Kyushu/Okinawa, 110% in Kanto, 40% in Yamaguchi
Low-band boost: 700 MHz platinum band service active since June 2024
Subscriber milestone: Surpassed 10 million subscribers in December 2025
Infrastructure: Over 100,000 total 4G/5G base stations nationwide

How to Check Your Exact Area

Before committing to Rakuten Mobile, verifying that you'll actually have reliable service where you live, work, and regularly travel is essential. Rakuten provides several official tools that let you check precise coverage rather than relying on vague marketing claims about "nationwide availability."

Official Coverage Map

Open the official service area map and search by your specific address, place name, or postal code. The interactive map displays coverage polygons for both 4G and 5G networks—toggle between layers to understand what technology is available at your location. The map also links to the partner coverage view showing where KDDI roaming remains active, and includes recent update timestamps so you know how current the data is. The interface operates primarily in Japanese, but the map itself is intuitive with address search functionality that works with English input.

Pan around the map to check not just your home address but also your workplace, your child's school, frequently visited shops, and any other locations where reliable connectivity matters. Coverage maps show theoretical availability based on tower placement and signal modeling, but real-world experience can vary inside buildings or in areas with terrain obstacles.

Subway Coverage List

If you regularly use underground subway systems for commuting or travel, check the station-by-station coverage list showing confirmed availability in underground sections. Subway coverage traditionally lagged behind street-level availability for newer carriers due to the expense and complexity of installing underground infrastructure, but Rakuten has made significant progress deploying service in major subway systems throughout Tokyo, Osaka, Nagoya, and other cities.

The list breaks down coverage by subway line and station, helping you identify whether your specific daily commute route has reliable service or if you'll experience dead zones between stations.

Prefecture Pages

Jump directly to your prefecture's dedicated page for map shortcuts focused on your region and information about nearby Rakuten Mobile shops for in-person assistance. These regional pages provide localized coverage details that help you zoom into your specific area more quickly than searching the nationwide map.

Coverage verification checklist: ✓ Check your exact home address ✓ Verify your workplace location ✓ Review your daily commute route ✓ Confirm subway stations if you use underground transport ✓ Check frequently visited locations (schools, shops, relatives' homes)

Reading the Map Without Guesswork

Understanding what the coverage map actually represents—and more importantly, what it doesn't guarantee—helps set realistic expectations and avoid disappointment after signing up.

Rakuten Area vs Partner Area

The distinction between "Rakuten area" and "partner area" fundamentally determines your network experience, though this difference has become less significant as Rakuten converts more territory to its own infrastructure. Rakuten area uses Rakuten's own cell towers and infrastructure, providing the full benefits of the network including unlimited high-speed data without caps. Partner area uses KDDI (au) roaming infrastructure where Rakuten's network hasn't yet been built—historically this came with usage caps, though recent plan changes have eliminated most restrictions.

The official coverage page at network.mobile.rakuten.co.jp/information/news/other/2131/ notes that roaming may still be active in some underground facilities, indoor environments, and specific locations where Rakuten's buildout remains incomplete. However, the company has been aggressively converting partner zones to its own network across all 47 prefectures, with roaming now limited primarily to challenging environments like deep subway stations, long tunnels, and remote mountainous areas where infrastructure deployment isn't economically viable yet.

5G vs 4G Availability

Even inside a mapped 5G coverage polygon, your phone may connect to 4G depending on your specific device capabilities, precise location within the coverage area, or momentary network load. Rakuten's official notices clarify that 5G is not provided in domestic partner roaming areas—only in Rakuten's own network zones—so if you're in an area that still uses KDDI roaming, you'll connect via 4G LTE regardless of whether 5G towers exist nearby.

The map shows theoretical availability based on tower placement and propagation modeling, but factors like building materials, terrain features, weather conditions, and network congestion can all affect whether your device actually achieves a 5G connection in practice. Use the map as a guide for potential availability rather than a guarantee of constant 5G connectivity.

Update Cadence and Data Currency

The area page lists data timestamps and revision notes showing when coverage information was last updated. Check these timestamps before making decisions based on map data—coverage continues expanding rapidly, so information from several months ago may not reflect current availability. Conversely, very recent updates might not yet show infrastructure that's under construction or planned for imminent deployment.

5G Today: Where It Is Growing

Rakuten continues widening Sub-6 mid-band 5G deployment throughout Japan with particularly impressive gains across southern and western regions. In 2025, the company reported substantial year-over-year increases across Kyushu, Okinawa, Shikoku, and Chugoku regions, with Okinawa prefecture approximately doubling its 5G footprint compared to January 2024 baseline measurements. The Kanto region covering Greater Tokyo saw 110% growth in 5G coverage, while Yamaguchi prefecture in western Honshu experienced 40% expansion.

These numbers represent the fastest mid-band 5G rollout happening first in dense population centers where subscriber density justifies infrastructure investment, then expanding along major transportation corridors connecting cities. The network now operates over 100,000 total 4G/5G base stations nationwide, heavily utilizing Massive MIMO (Multiple Input Multiple Output) antenna technology that improves capacity and efficiency. Rakuten surpassed the 10 million subscriber milestone in December 2025, providing the revenue base to continue aggressive infrastructure expansion.

Why this matters for users: Sub-6 mid-band 5G (frequencies around 3.4-3.8GHz) improves both network capacity and connection consistency compared to 4G LTE. You'll experience faster download and upload speeds for large file transfers, lower latency for real-time applications like video calls or online gaming, and better performance in crowded environments where many users share the same cell tower. The 700 MHz platinum band launched in 2024 complements this by filling indoor and edge coverage gaps where higher frequencies struggle to penetrate obstacles.

Geographic priorities: Expect the fastest 5G expansion in major metropolitan areas (Tokyo, Osaka, Nagoya, Fukuoka, Sapporo), along Shinkansen high-speed rail corridors, near universities and business districts with high subscriber density, and throughout popular tourist destinations. Rural areas will see 4G improvements before extensive 5G deployment due to economics.

Subways, Trains, and Travel Corridors

Maintaining reliable connectivity while moving at high speed through tunnels or underground systems presents technical challenges that newer carriers like Rakuten face when competing against established networks. However, Rakuten has made substantial progress deploying infrastructure along major transportation routes and underground systems.

Subway Coverage

Rakuten publishes a comprehensive subway station list showing where service is available between stations on underground portions of major subway systems. The list indicates confirmed coverage for each line and station, helping commuters determine whether their specific route maintains connectivity or experiences dead zones during underground travel.

Major subway systems in Tokyo, Osaka, Nagoya, Fukuoka, and Sapporo have seen extensive Rakuten deployment, though some older or less-trafficked lines may still have gaps. If subway connectivity is critical for your daily commute—perhaps you need to take video calls, stream music, or access real-time information while underground—check your specific lines before committing to the service.

Long-Distance Rail Performance

Independent testing conducted by Opensignal along the Tokaido Shinkansen—Japan's busiest high-speed rail corridor connecting Tokyo, Nagoya, Kyoto, and Osaka—showed strong overall performance across Japan's major networks, with Rakuten leading upload speeds along that route during testing. While this is just one data point on one specific corridor, it suggests Rakuten has prioritized deployment along major transportation arteries where subscriber usage is highest.

Use such testing reports as directional indicators rather than guarantees, then verify your specific travel routes using the official coverage map. Coverage along rail lines can vary significantly depending on terrain (tunnels, mountains, urban vs rural), infrastructure investment priorities, and whether routes pass through Rakuten areas or partner zones.

Devices and Compatibility

Before blaming coverage for connectivity issues, verify that your device actually supports Rakuten Mobile's network fully. Some phones—particularly older models or devices designed exclusively for other markets—lack support for all of Rakuten's frequency bands or required features like VoLTE (Voice over LTE) calling.

Use Rakuten's BYOD (Bring Your Own Device) compatibility checker to verify your specific phone model and OS version are fully supported. The checker confirms whether your device supports Rakuten's required 4G LTE bands, 5G frequencies if you have a 5G-capable phone, VoLTE for voice calling, and proper configuration for the Rakuten Link calling app.

Keep your device's OS updated to the latest iOS or Android version that Rakuten officially supports—carrier settings, VoLTE profiles, and IMS (IP Multimedia Subsystem) registration often require recent software versions to function correctly. Some imported phone models from international markets may need specific carrier settings updates to register properly on Rakuten's network, even if they technically support the right frequencies.

If you experience coverage issues that friends with Rakuten don't face in the same locations, device compatibility or configuration problems may be the culprit rather than actual coverage gaps.

When the Map Says "Covered" But Signal Is Weak

Coverage maps show theoretical availability based on tower placement, signal propagation modeling, and ideal conditions. Real-world signal strength can differ significantly based on environmental factors that maps can't fully account for.

Environmental Challenges

Indoor environments, underground facilities, large shopping malls, office building interiors, and transportation tunnels can substantially reduce signal strength even in areas marked as well-covered on the map. Building construction materials matter enormously—steel-reinforced concrete, metal-framed structures, and energy-efficient window coatings all block cellular signals far more effectively than traditional wood-frame construction. Even within a single building, rooms toward the interior with multiple walls between you and the nearest cell tower experience weaker signals than rooms near windows.

Rakuten's area page notes at network.mobile.rakuten.co.jp/area/ that calculated coverage maps may differ from real-world conditions due to factors like terrain features, building structures, weather conditions, and temporary network issues. These aren't excuses—they're realistic acknowledgments that radio frequency propagation is complex and affected by countless variables.

Troubleshooting Weak Signal

If you're inside a mapped coverage area but experiencing weak signal or dropped connections, try these practical steps:

Move closer to windows or exterior walls where fewer obstacles block signals between your phone and the cell tower. Even moving from an interior room to a room with exterior walls can improve signal dramatically.

Step outside or onto a balcony to test whether the issue is building penetration or actual coverage gap. If signal improves significantly outdoors, the problem is indoor penetration rather than tower coverage.

Enable Wi-Fi Calling if you have reliable Wi-Fi connectivity at the location with weak cellular signal. Wi-Fi calling routes voice calls and SMS through your internet connection, completely bypassing the cellular network. Access this feature in your phone's settings (iPhone: Settings → Phone → Wi-Fi Calling; Android: Settings → Network & Internet → Mobile Network → Advanced → Wi-Fi Calling).

Capture time, location, and circumstances if issues persist despite troubleshooting. Contact Rakuten support with specific details—"I consistently have no signal in the northwest corner of the third floor at my workplace building at [address]" is actionable information that engineers can investigate, while "coverage is bad sometimes" is too vague to address.

Partner Coverage and Roaming

Understanding partner roaming helps explain why your phone might occasionally show "KDDI" or "au" instead of "Rakuten" in your status bar, and what that means for your service.

Rakuten has been systematically converting partner roaming zones to its own network infrastructure across all 47 prefectures since launching the network. Where Rakuten initially relied heavily on KDDI roaming to provide nationwide coverage while building its own towers, the company now operates primarily on its own infrastructure with roaming limited to specific challenging environments.

Partner roaming remains active primarily in deep subway stations where infrastructure deployment is expensive and complex, long transportation tunnels through mountains, underground shopping passageways and facilities, and certain rural mountainous areas where tower deployment isn't economically justified given low population density. The official notice at network.mobile.rakuten.co.jp/information/news/other/2131/ provides details on where roaming continues.

You can consult KDDI's coverage map as a reference for roaming availability—the link is provided from Rakuten's area page. However, roaming coverage is less relevant now than it was in Rakuten's early years, as the company's own network reaches most areas where subscribers actually live and travel.

Extra Tools for Power Users

While Rakuten's official coverage map should be your primary reference, crowd-sourced tools can help you sanity-check tower placement and real-world signal reports from actual users. Treat these supplemental resources as additional data points rather than authoritative sources.

nPerf Coverage Heatmaps

nPerf.com provides crowd-sourced coverage heatmaps showing signal strength data collected from users running speed tests across Japan. The heatmaps display relative signal quality in different regions based on actual user measurements rather than theoretical modeling, helping identify areas where real-world performance differs from official maps.

CellMapper Tower Plotting

CellMapper plots Rakuten Mobile cell tower locations and coverage sectors based on crowd-sourced data from users running the CellMapper app (MCC 440, MNC 11 identifies Rakuten on Japan's cellular network codes). This can help you understand where towers are physically located relative to your address, which directions they broadcast toward, and approximate coverage boundaries based on user-reported connections.

These tools complement official maps but shouldn't replace them—crowd-sourced data reflects where users have actually tested, which may not include less-populated areas or recently deployed infrastructure.

Coverage Checklist for New Users

Before signing up for Rakuten Mobile, systematically verify these critical points to avoid surprises:

✓ Check your exact address on the official coverage map—not just general city-level coverage but your specific street and building

✓ Confirm device compatibility with the BYOD checker—compatibility issues cause more "coverage" complaints than actual network gaps

✓ Review subway coverage if you use underground transport regularly for commuting or travel—check your specific lines, not just overall subway availability

✓ Understand partner vs Rakuten areas for your daily routes—though this matters less now than in previous years as Rakuten's own network has expanded

✓ Test signal strength with friends, family, or colleagues using Rakuten Mobile in your area—real-world user experience from people who actually use the network where you live beats any map or review

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Key Links

Official coverage map: Service area map with 4G/5G toggles
Subway station coverage list: Underground availability by line
Prefecture index: Quick access by prefecture
BYOD compatibility check: Device compatibility checker

Rakuten Mobile Japan Coverage: The 2026 Guide