Rakuten Mobile Indoor Coverage: Which Buildings Get Good Signal?

Honest guide to Rakuten Mobile's indoor coverage in 2026. Learn how Platinum Band improves building penetration, which buildings get good signal, and practical solutions when coverage is weak.

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Last verified: January 13, 2026 (JST)

Indoor coverage historically represented Rakuten Mobile's most significant challenge—but that narrative fundamentally changed in 2024 with the Platinum Band rollout. Here's the honest assessment in 2026: if you're near windows or in modern buildings with Platinum Band coverage, you'll likely experience reliable connectivity. Deep inside concrete buildings with reflective Low-E glass still presents challenges, though substantially improved compared to 2023 conditions. This guide explains which building types naturally support good Rakuten coverage, which environments remain problematic, and the practical fixes that work when signal drops indoors.

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How Platinum Band Changed Indoor Coverage

In June 2024, Rakuten Mobile launched commercial service on the 700MHz "Platinum Band"—a lower frequency allocation that fundamentally changed indoor coverage characteristics. Unlike the higher frequencies Rakuten previously relied upon, 700MHz radio waves penetrate building walls more effectively because lower frequency waves naturally travel better through physical obstacles like concrete, steel, and glass.

What this means practically: you'll experience better connectivity in basements and underground stations where signals must penetrate multiple floors of concrete and earth. Building interiors far from windows show substantial improvement as 700MHz signals push through exterior and interior walls more effectively than higher bands. Expanded rollout targeting 99.9% population coverage by mid-2026 means gradually improving service in previously weak areas as more towers activate with platinum band capability.

However, platinum band isn't a magic solution erasing all indoor challenges. Deep inside large buildings, far from exterior walls, signal still weakens significantly. Buildings with reflective glass that specifically blocks radio frequencies continue causing attenuation. Real-world performance varies substantially by specific site deployment patterns, building materials and architecture, and whether your device actually supports Band 28 (700MHz).

By March 2025, Rakuten reported a 40% improvement in connectivity in targeted areas, with particularly strong gains in large commercial facilities across expanded regions. These aren't trivial improvements—they represent substantial practical enhancement for users who spend time in challenging indoor environments.

Buildings That Get Good Signal

Best Indoor Coverage Environments

Modern commercial buildings with Platinum Band deployment naturally support strong indoor connectivity, particularly shopping malls with outdoor-facing storefronts providing numerous exterior wall access points. Office buildings near major stations in urban areas benefit from dense tower deployment with overlapping coverage. Buildings constructed with signal-friendly materials like wood or lightweight steel create minimal attenuation. Ground floor locations and near-window spaces maintain strongest signal through direct line-of-sight to outdoor towers.

Low-rise buildings of 1-4 stories experience less signal interference from their own structure. Easier line-of-sight to nearby towers means signals don't need to penetrate as many floors and walls. Wooden or light construction materials common in low-rise structures create minimal blocking.

Buildings near base stations enjoy proximity advantages—being within 500 meters of a Rakuten tower (check CellMapper: https://www.cellmapper.net/map?MCC=440&MNC=11) means strong outdoor signal naturally carries better indoors through sheer signal strength overwhelming some attenuation.

Buildings With Coverage Challenges

Difficult Indoor Coverage Environments

Buildings with reflective or Low-E (low-emissivity) glass present unique challenges. Modern energy-efficient buildings increasingly use Low-E glass that blocks infrared radiation to improve climate control—but these same coatings also block radio waves used for cellular communication. Reflective glass facades on skyscrapers significantly reduce signal penetration. Windows designed to reflect heat also reflect cellular signals back outside rather than allowing them to penetrate interiors.

Deep inside concrete high-rises, center offices and apartments far from exterior walls face natural attenuation challenges. Elevator cores and interior hallways surrounded by concrete create signal dead zones. Basements and underground parking show improvement with Platinum Band but still represent challenging environments where signals must penetrate substantial material thickness.

Older buildings in areas without Platinum Band deployment don't benefit from the improved penetration characteristics. Check the coverage map to confirm Platinum Band availability in your specific area: https://network.mobile.rakuten.co.jp/area/

Dense concrete construction creates the biggest penetration challenge. Industrial-strength reinforced concrete blocks, absorbs, and reflects RF waves simultaneously. All carriers struggle with concrete buildings—this isn't unique to Rakuten. The platinum band helps level the competitive playing field but doesn't eliminate physical material challenges.

How to Check Coverage Before You Sign Up

Test Before Committing to Service

Visit your workplace, home, or frequently-visited location during the day with a Rakuten Mobile user who can lend their phone, or bring a trial SIM if available. Test in multiple locations systematically: near windows where signal concentrates; center of the building far from exterior walls; basement levels if present. Try making actual calls and checking data speeds rather than just looking at signal bars.

Check the official coverage map to verify Platinum Band availability in your area and confirm dense tower coverage on CellMapper showing multiple nearby towers providing redundancy. Ask building management or neighbors directly: "Does Rakuten Mobile work well here?" Check community forums specific to your building or area for user reports about coverage experience.

Test at different times of day since signal can vary with network congestion. Lunch hours and evening rush hours may show reduced speeds in areas with high user density even if coverage itself remains solid.

Solutions When Indoor Signal Is Poor

Wi-Fi Calling: The Best Workaround

Rakuten Link offers free Wi-Fi calling when cellular signal weakens, becoming your primary solution for poor indoor coverage environments. Install the Rakuten Link app for iOS or Android, log in with your Rakuten ID, and enable Wi-Fi Calling in your phone settings: iPhone through Settings → Cellular → Wi-Fi Calling → Enable; Android via Settings → Network & Internet → SIMs → Wi-Fi Calling → Enable. Connect to Wi-Fi and make calls through Rakuten Link.

Benefits include unlimited free domestic calls over Wi-Fi without counting toward any usage limits, functionality even with zero cellular signal bars, your normal phone number displaying to recipients, and no counting toward your data quota since it uses Wi-Fi rather than cellular data.

Submit Signal Improvement Requests

Rakuten Mobile accepts signal improvement requests from users experiencing consistent poor coverage in specific buildings or areas. Visit the official website to locate the signal improvement request form. Provide specific location details including address, building name, and floor number. Describe the issue clearly—no signal, slow data, or dropped calls. Rakuten evaluates requests and potentially adds coverage infrastructure in areas showing consistent user issues.

While not guaranteed, user reports indicate Rakuten does respond to these requests, especially in densely populated areas where infrastructure investment serves many potential subscribers. Your feedback directly influences deployment priorities.

Move Closer to Windows

Simple but effective: signal strength naturally peaks near exterior walls and windows providing direct line-of-sight to outdoor towers. Keep your phone near a window when making important calls. Consider desk or bed placement near windows if signal quality matters significantly for your work or lifestyle patterns.

Check Device Compatibility

Ensure your phone supports Band 28 (700MHz) for platinum band access. Many overseas models lack Japan's Platinum Band support, preventing you from benefiting from Rakuten's most significant indoor coverage improvement regardless of tower density. Use the official compatibility checker: https://network.mobile.rakuten.co.jp/en/product/byod/

Even if your model appears listed, overseas variants may have limitations compared to Japanese domestic models. Check carefully and consider whether your specific variant includes Band 28 support.

What's Coming: 2026 Improvements

Rakuten Mobile targets 99.9% population coverage by mid-2026 with continued Platinum Band deployment across remaining areas. Expect more base stations in urban areas providing additional capacity and coverage redundancy. Expanded underground coverage in subways and shopping areas as infrastructure sharing agreements enable equipment installation. Better coverage in large commercial buildings as platinum band activation reaches more sites. Continued improvements in previously weak areas as deployment progresses through lower-priority regions.

If you're considering Rakuten Mobile but your building shows marginal coverage currently, conditions may improve significantly over the next six months as deployment continues. The trajectory shows consistent improvement rather than stagnation.

The Honest Take

Good enough for most people? Yes, especially with Wi-Fi Calling as backup strategy. If you spend most time in modern urban buildings, near windows, or have reliable Wi-Fi access, Rakuten Mobile works well in 2026. The platinum band deployment represents real, measurable improvement over 2023 conditions.

Not for everyone? True. If you work deep inside a concrete building with poor Wi-Fi, need perfect signal in elevators between meetings, or frequently travel to rural areas without Platinum Band coverage, consider carriers with more established infrastructure and decades of deployment optimization.

The Platinum Band rollout is genuine and measurable—just set realistic expectations based on your specific building type and daily locations. Testing during trial periods reveals whether Rakuten meets your personal requirements better than generic coverage statistics.

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Quick Reference

Location Type Signal Quality Platinum Band Impact Best Solution
Near windows Good Much better Native signal
Modern mall Good Much better Native signal
Office center Variable Improved Wi-Fi Calling
Concrete basement Poor Improved Wi-Fi Calling
Low-E glass building Poor Limited help Wi-Fi Calling
Underground shopping Variable Improved Test before signup

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