Destination guide

How to Avoid Roaming Charges in Japan (2026)

Japan is one of the easiest places to stay connected cheaply — if you skip roaming and use an eSIM. Here is exactly how.

Updated June 2026Prices verified weekly

How to avoid roaming

36.9M (2024) arrive in Japan every year. AT&T charges each one $10/day to use data. Airalo offers 20GB on NTT docomo for $22.49. A 10-day visit saves $78 per traveler.

June 2026 verified2+ networksFrom $0.61/GB4 providers comparedUpdated June 2026

! Danger

US carriers charge $10/day or $2.05/MB for data roaming in Japan. A single week of casual phone use costs $70–200+.

&check; Solution

A travel eSIM from Airalo connects to KDDI/au's 5G network at $0.61/GB. Same towers, same coverage, no roaming middleman.

How to avoid roaming charges in Japan

Verizon TravelPass runs $10/day in Japan — identical to AT&T's International Day Pass. T-Mobile includes international data but throttles to 256 Kbps, slow enough that Maps tiles fail to load. All three carriers connect through NTT docomo's towers. None operate their own infrastructure here. The $10/day fee pays for the billing agreement, not the signal quality.

Bypass all three carriers by installing a Japan eSIM before departure. Disable data roaming on your home SIM in Settings. A 20GB plan on NTT docomo costs $22.49 for 10 days at full speed. After landing, activate the eSIM as your data line. Same NTT docomo towers, same coverage map, no daily fee.

The roaming trap in Japan

Two phones on AT&T International Day Pass in Japan: $20/day, $200 over 10 days. Four phones: $40/day, $400 for the week. A family trip on Verizon TravelPass costs the same — $10 per device per day on NTT docomo. Four eSIMs on NTT docomo at $22.49 each: $89.96 total for 20GB per device. That is $310 in savings for the family. Each eSIM connects independently to NTT docomo — no shared pool, no per-device daily trigger.

How much data activities cost in Japan

Roaming vs eSIM cost per activity in Japan (AT&T $2.05/MB vs eSIM at $$0.61/GB)
Activity	Data Used	Roaming Cost	eSIM Cost
Send WhatsApp photo	3 MB	$6.15	$0.00
10 min Google Maps	5 MB	$10.25	$0.00
10 min Instagram scrolling	50 MB	$102.50	$0.03
1 hour video call (Zoom)	1.0 GB	$2099.20	$0.61
30 min Spotify	45 MB	$92.25	$0.03
Check Google Translate (10 queries)	2 MB	$4.10	$0.00

Roaming costs by trip length for Japan

Four phones on AT&T in Japan: $40/day. Over 10 days: $400. Each device bills $10/day independently on NTT docomo — a child's game, a partner's map search, a grandparent's text all trigger separate daily charges. Four eSIMs on NTT docomo cost $89.96 total for 20GB each. Family savings: $310.04. Per device, per day: AT&T = $10. eSIM = $2.25. The math scales as badly for families as it does for individuals.

What your carrier charges in Japan

AT&T International Day Pass charges $10/day in Japan. Verizon TravelPass charges $10/day. Both connect through NTT docomo and offer the same coverage map. T-Mobile includes international data on most plans, but throttles speeds to 256 Kbps — slow enough that Google Maps tiles fail to load and ride-hailing apps time out. All three carriers use NTT docomo's towers in Japan. None of them operate their own infrastructure here. The $10/day fee pays for the billing agreement between your home carrier and NTT docomo, not for better signal or faster speeds. NTT docomo delivers 225 Mbps to local subscribers and eSIM users alike. A Japan eSIM on NTT docomo costs $22.49 for 20GB — the same network, the same towers, at $1.12/GB instead of $10/day.

The technical side of roaming charges in Japan

AT&T's International Day Pass in Japan is not truly unlimited. Your domestic data cap applies to roaming — once exceeded, AT&T throttles your connection to 128 Kbps on NTT docomo's network. At 128 Kbps, Google Maps tiles load in 20-30 seconds. Ride-hailing apps time out. Video calls are unusable. The $10/day charge does not pause when throttling starts — you pay the full daily rate for slow-speed access. Travelers with lower domestic data plans hit the throttle fastest. An eSIM provides a dedicated data allocation on NTT docomo that does not interact with your domestic cap. 20GB at $22.49 gives you a separate data balance that does not depend on what you used before your trip.

Background data leaks in Japan

Location Services on your phone ping NTT docomo's towers every few minutes in Japan. Find My, Maps, Weather, and ride-hailing apps all request location data in the background. Each ping transfers 0.5-2 MB. Over a full day, location pings accumulate 10-30 MB of silent cellular data. At $2.05/MB, that is $20-60 per day in charges you never authorized. Disable location services for non-essential apps before landing: Settings > Privacy > Location Services > review each app. Keep Maps and emergency services active, disable everything else. An eSIM on NTT docomo at $3.49 for 1GB routes these pings through flat-rate data instead of AT&T's per-MB billing.

Airport SIM counter vs eSIM in Japan

You land in Japan at 11:45pm and the airport SIM counter is closed. The next shift starts at 7am. Your options: pay AT&T $10/day on NTT docomo until morning, or use a pre-installed eSIM that activates the moment airplane mode turns off. Airport SIM counters at Narita (NRT) / Haneda (HND) operate on local business hours, not your flight schedule. Red-eye arrivals, early-morning landings, and delayed flights all arrive outside counter hours. An eSIM on NTT docomo installs before you leave home — 1GB for $3.49, active on landing regardless of the hour. No counter, no waiting for business hours, no $10 overnight charge.

Order of operations: disable roaming first, then install your eSIM in Japan

! Do this before step 2

Disable data roaming on your home SIM first. If your home SIM is still roaming-enabled when your eSIM activates, your carrier can charge both lines simultaneously. Settings → Cellular → Cellular Data Options → Data Roaming: OFF.

Disable data roaming on your home SIM

Go to Settings › Cellular › Cellular Data Options and turn Data Roaming OFF. This is the most critical step. Skipping it means Japan roaming charges can still hit your home carrier bill.

Buy a travel eSIM

Get a plan from Airalo at $0.61/GB. Do this at home on WiFi before you fly — QR code delivery takes under 60 seconds.

Install the eSIM profile

Open phone Settings › Cellular › Add eSIM. Scan the QR code or tap the install link in your confirmation email.

Set eSIM as default data on arrival

After landing in Japan, go to Settings › Cellular and set your travel eSIM as the primary data line. It connects to KDDI/au within minutes.

Keep home SIM for calls via WiFi Calling

Your home number stays reachable for free over WiFi. You pay eSIM rates for data — 85–95% less than roaming.

Need help with device compatibility? Check eSIM compatible phones or our how eSIMs work guide before purchasing.

iPhone and Android guide for visiting Japan

Enable WiFi Calling before traveling to Japan to keep your home number active without cellular roaming. On iPhone: Settings > Cellular > Wi-Fi Calling > On. On Android: Settings > Connections > Wi-Fi Calling > On. WiFi Calling routes voice calls and texts through any WiFi connection using your home carrier number, bypassing NTT docomo's cellular network entirely. This means your home SIM stays useful for calls — to family, for 2FA codes, for US-based contacts — without triggering AT&T's $10/day data charge. Your eSIM on NTT docomo handles all cellular data at $22.49 for 20GB. WiFi Calling plus eSIM data creates a two-layer setup that eliminates roaming charges while maintaining full functionality of both phone numbers. 5G is available on NTT docomo — your device connects automatically if your plan includes 5G access.

eSIM marketplace for Japan

eSIM alternatives

Best eSIM providers for Japan

Ranked by price, coverage, and reliability in Japan.

eSIM providers for Japan, verified June 2026
Provider	Rating	Countries	From	Best for	Actions
Airalo#1 Pick	4.8 out of 5 stars4.8	200+	$4.50/GB	Best Overall	Get Airalo →Review
Nomad	4.4 out of 5 stars4.4	112+	$3.00/GB	Best Budget	Get Nomad →Review
Saily	4.5 out of 5 stars4.5	150+	$3.99/GB	Best Privacy	Get Saily →Review
Holafly	4.6 out of 5 stars4.6	178+	$2.99/day	Best Unlimited	Get Holafly →Review

Prices verified June 2026By AvoidRoaming Guides

We earn a commission when you purchase through links on this page. It does not change our rankings or the price you pay.

Provider pick

Why Airalo for Japan

Airalo leads on price for Japan with 20GB at $22.49 on NTT docomo's network. AT&T International Day Pass charges $10/day for the same NTT docomo towers — $100 over 10 days. Airalo connects through identical infrastructure at $1.12/GB. The savings come from removing the carrier middleman. Your home carrier negotiates roaming agreements that add markup at every layer. Airalo contracts directly with NTT docomo, passing the lower rate to you. Plans start at $3.49 for 1GB with no daily activation fee.

Networks

Network coverage in Japan

These are the carrier networks that bill your home operator $10 per day when you roam in Japan: KDDI/au and NTT docomo. Airalo and the other 3 eSIM providers compared here connect through KDDI/au — the same towers, the same signal, zero carrier roaming markup. NTT docomo handles secondary coverage in rural and suburban areas and serves as a fallback network for providers that support multi-carrier switching. AT&T International Day Pass and Verizon TravelPass use this exact same KDDI/au infrastructure when they charge $10 per day. The charge is for the billing relationship, not the signal. Japan eSIM plans on KDDI/au start at $3.49 for 1GB — the same network access for a fraction of the carrier roaming price.

Mobile networks in Japan — eSIM-compatible carriers, June 2026
Operator	Types
KDDI/au	5G
NTT docomo	4G

Network coverage data verified June 2026.

Speed

Speed test results for Japan

Japan has widespread 5G coverage through NTT docomo. 99.2% population coverage as of 2025; all four carriers actively expanding. Average download speeds reach 225 Mbps on NTT docomo's network — the same infrastructure AT&T charges $10/day to access via roaming. Public WiFi availability is excellent. Free WiFi at stations, convenience stores, and most cafes; Japan WiFi auto-connect app available. Signal held strong in Tokyo Metro underground and Shinkansen tunnels. Minor drops in rural Hakone mountain area on KDDI.

Connectivity

WiFi and internet access in Japan

WiFi in Japan is excellent, but it cannot prevent roaming charges on its own. Your phone still searches for NTT docomo between hotspots. Walking from a WiFi-enabled cafe to the street triggers an AT&T connection — $10 charged instantly. Background app refreshes, push notifications, and location services all attempt cellular data the moment WiFi drops. The only reliable prevention is disabling data roaming on your home SIM. An eSIM on NTT docomo then handles all data at local rates. Use WiFi as a backup for heavy downloads. Use the eSIM for everything else. Plans start at $3.49 for 1GB.

Privacy

Data privacy in Japan

Japan places no restrictions on VPN usage. Travelers can run any VPN provider on NTT docomo's network without interference. This matters because WiFi availability is excellent — and every unsecured WiFi connection exposes banking credentials, email passwords, and payment details. An eSIM on NTT docomo at $3.49 for 1GB provides a private cellular connection that is inherently more secure than public WiFi. Layer your VPN on top of the eSIM connection for maximum privacy. This combination eliminates both AT&T's $10/day roaming charge and the security risks of relying on hotel WiFi.

Pricing

eSIM pricing for Japan

What a travel eSIM costs in Japan versus carrier roaming.

Without a plan, AT&T International Day Pass costs $10/day in Japan. A 10-day trip totals $100. Verizon TravelPass bills the same $100 for identical access. Per-MB rates without any pass run $2.05/MB — one hour of background use can exceed $200. Airalo's 20GB plan covers the same 10 days at $22.49, saving $78 (78%) against AT&T on the same Japan carrier infrastructure. Plan breakdown by tier: 1GB: $3.49 ($3.49/GB), 3GB: $6.99 ($2.33/GB), 5GB: $9.49 ($1.90/GB), 10GB: $15.99 ($1.60/GB), 20GB: $22.49 ($1.12/GB). Unlimited daily data starts at $3.49/day with 2GB at full speed before throttling. The best per-GB rate sits at the 20GB tier — $1.12/GB.

Travel eSIM plan pricing for Japan — verified June 2026
Data	eSIM Price	Per GB
1GB	$3.49	$3.49
3GB	$6.99	$2.33
5GB	$9.49	$1.90
10GB	$15.99	$1.60
20GB	$22.49	$1.12
Unlimited / day	$3.49/day	—

Prices sourced from provider websites and updated weekly.

Pricing verified June 2026

Multi-country

Visiting more than just Japan?

Japan eSIM plans start at $22.49 for 20GB on NTT docomo. Neighboring countries: Afghanistan: $102.90 for 20GB; Armenia: $46.56 for 20GB; Azerbaijan: $38.77 for 20GB. AT&T charges $10/day in every one of these countries — the rate does not adjust by destination or local cost of living. A Asia regional eSIM bundle often matches the cost of a single-country plan while covering all neighboring countries. Compare the regional bundle price against individual country plans before purchasing. If your trip crosses any border — even for a day trip from Japan to Afghanistan, Armenia, and Azerbaijan — the regional bundle eliminates the per-country AT&T penalty.

Local tips

Practical details for your trip to Japan

What your carrier does not tell you about Japan: Local prepaid SIMs run $15-30 for 3GB / 30 days. eSIM plans at $3.49 for 1GB remove the store visit. Airport SIM cards cost roughly $20-50 for 5-15GB / 7-30 days. eSIM plans start lower and activate before you land. Airport SIM counter wait times run 5-15 min; vending machines available 24/7. LINE app is essential for local communication; download before arrival.

Timing

Peak season connectivity in Japan

Prices stable year-round; airport counter prices 20-30% higher than city. AT&T's $10/day roaming charge does not shift at all — it stays fixed during Mar-Apr and Oct-Nov and every other month. Verizon TravelPass holds at the same $10/day year-round. This means roaming costs represent a larger percentage of your travel budget during off-peak months when flights are cheaper. A 10-day trip always costs $100 in AT&T day passes regardless of season. A 20GB eSIM on NTT docomo at $22.49 stays flat too, but at a fraction of the carrier rate. The savings percentage increases when your other travel costs drop.

Avoid these

Mistakes that cost travelers in Japan

WiFi Assist left on

iOS WiFi Assist automatically switches to cellular when hotel WiFi weakens. In Japan, this routes data through your home SIM on NTT docomo, triggering AT&T's $10/day charge mid-session. Disable WiFi Assist under Settings > Cellular before departure.

iCloud backup over cellular

iCloud backs up overnight using any available data connection. A 500 MB backup at $2.05/MB costs over $1,000 on NTT docomo in Japan. Disable iCloud backup on cellular in Settings > Cellular before landing.

Day pass midnight reset misunderstood

AT&T's $10/day pass resets at midnight JST (UTC+9) time — not local time in Japan. Landing at 10pm local time can trigger two separate $10 charges before you sleep. An eSIM on NTT docomo at $3.49 has no midnight reset.

Buying airport SIM without comparing

Airport SIM counters in Japan charge $20-50 for 5-15GB / 7-30 days for physical SIMs. eSIM plans on NTT docomo start at $3.49 for 1GB — lower cost, no queue, pre-installed before landing.

Leaving roaming on just in case

Keeping roaming on "just in case" costs $10/day on NTT docomo whether you use any data or not. A single background push notification triggers the full charge. There is no safe way to leave roaming on while avoiding the fee in Japan.

The bottom line

The bottom line on roaming in Japan

NTT docomo delivers 225 Mbps in Japan. AT&T accesses this same network for $10/day. An eSIM accesses the same network for $22.49 total over 10 days. The download speeds are identical. The coverage map is identical. The tower infrastructure is identical. The $10/day AT&T charge pays for the roaming billing agreement between AT&T and NTT docomo, not for better signal or faster speeds. Remove the billing layer, keep the same NTT docomo signal, and save $77.51.

Before you fly

Last-minute checklist for Japan

Disable data roaming: Settings > Cellular > Data Roaming OFF (do this before departure).

Install a Japan eSIM while on home WiFi — plans from $3.49 for 1GB on NTT docomo.

Save 110/119 as Japan's emergency number in your contacts.

Pack a Type A/B power adapter for Japan.

Local currency is JPY (¥).

Time zone: JST (UTC+9). Adjust your phone clock on arrival.

After landing at Narita (NRT) / Haneda (HND): turn off airplane mode, activate your eSIM as the data line.

Keep your home SIM active for calls and texts via WiFi Calling.

Common questions

Everything you asked about roaming in Japan, answered

What settings should I change before traveling to Japan?

Complete this checklist 24 hours before departure. First: disable Data Roaming (iPhone: Settings > Cellular > Data Roaming off; Android: Settings > Mobile Networks > Data Roaming off). Second: turn off Background App Refresh (iPhone: Settings > General > Background App Refresh > Off). Third: disable automatic app updates (App Store > Settings > App Downloads off). Fourth: install your Japan eSIM and set it as your data line. Fifth: enable WiFi Calling on your home SIM for free calls over WiFi. This 5-step process prevents all carrier charges from NTT docomo and saves $10/day versus AT&T's Day Pass.

Can background apps trigger roaming charges in Japan?

Yes, background apps are one of the most common sources of surprise roaming bills. With data roaming enabled and no day pass, AT&T charges $2.05/MB in Japan. Background App Refresh on iPhone syncs mail, news, and social apps every 15-30 minutes automatically, including at 3am while you sleep. A single overnight background sync session can accumulate $50-200 in charges without you opening your phone. Disable Background App Refresh before travel: Settings > General > Background App Refresh > Off. Then disable data roaming. An eSIM replaces carrier data entirely. Background syncs bill against the eSIM's flat-rate data at $3.49, not your home carrier's per-MB rate.

How do I check how much roaming data I used in Japan?

On iPhone: Settings > Cellular > scroll down to "Current Period Roaming" to see total roaming data consumed. On Android: Settings > Connections > Data Usage > Mobile Data Usage > select your SIM, then filter by roaming. Check this immediately after landing in Japan to catch charges early. AT&T also sends usage alerts at 50%, 75%, and 100% of Day Pass data limits. Log into the myAT&T or My Verizon app for itemized charges from NTT docomo. If roaming data appeared, enable Airplane Mode, disable data roaming, and call your carrier within 48 hours. Prevent future charges with an eSIM at $3.49 for 1GB.

Does an eSIM get the same coverage as roaming in Japan?

Yes. An eSIM connects to NTT docomo, the same network infrastructure AT&T and Verizon use for roaming in Japan. You get identical towers, identical coverage area, and the same 5G speeds. The only difference is billing: your carrier charges $10/day or $2.05/MB for roaming access to these towers, while the eSIM charges $1.12/GB for the same connection. There is no coverage penalty for using an eSIM. In many cases, eSIM data speeds are faster because carrier roaming agreements sometimes throttle international users to lower priority.

How much does roaming cost for a family traveling to Japan?

AT&T and Verizon charge Day Pass fees per line, not per account. A family of four on AT&T Day Pass pays $40/day in Japan, totaling $400 for a 10-day trip. Children's phones are particularly risky because apps and games download updates in the background. One child's iPad streaming a YouTube video at $2.05/MB racks up $400+ in under an hour. Four eSIMs on NTT docomo cost roughly $27.96 total for 3 GB each. Share one eSIM's hotspot to cover all devices and cut costs further.

Should I use WiFi Calling or an eSIM for calls in Japan?

Use both. WiFi Calling routes calls through your home carrier over WiFi, using your home minutes. It is free on most US carrier plans. The limitation: WiFi Calling only works when connected to WiFi, not mobile data. An eSIM on NTT docomo at $3.49 gives you mobile data everywhere. Use WhatsApp or FaceTime over eSIM data for calls when WiFi is unavailable. Enable WiFi Calling before departure: iPhone Settings > Phone > WiFi Calling. When on hotel WiFi, calls route free through your home carrier. When on mobile data, use WhatsApp calls through the eSIM.

What happens to my home number while using an eSIM in Japan?

Your home number stays fully active. With dual-SIM setup, your home SIM keeps your phone number for calls and texts while the Japan eSIM handles data on NTT docomo. You receive calls on your home number. SMS messages arrive normally. Data routes through the eSIM at $3.49 instead of your carrier's $10/day roaming. On iPhone, set Cellular Data to the eSIM line and Default Voice to your home SIM. Both lines work simultaneously. Your home number is not affected by the eSIM installation and remains active throughout your entire trip.

Which network does a Japan eSIM connect to?

Travel eSIMs for Japan connect through NTT docomo and KDDI/au, the same carrier infrastructure your home carrier's roaming partners use. The 5G network delivers up to 225 Mbps download speed. AT&T and Verizon both route their roaming through the same towers and charge $10/day for access. An eSIM connects to the same infrastructure for $3.49/GB with no daily activation fee.

Should I enable WiFi Calling before traveling to Japan?

Yes. WiFi Calling lets you make and receive calls using your home number over any WiFi network without roaming charges. On iPhone: Settings > Phone > WiFi Calling > toggle on. On Android: Settings > Connections > WiFi Calling > toggle on. Test it at home before departure. With WiFi Calling active in Japan, incoming calls ring through WiFi instead of NTT docomo's roaming network. Combined with an eSIM for data ($3.49), you have full phone functionality at zero carrier roaming cost. AT&T, Verizon, and T-Mobile all support WiFi Calling. Check with your carrier to confirm it works for international destinations.

Is there a data limit on carrier roaming plans for Japan?

AT&T Day Pass includes your domestic data plan while roaming, but throttles to 128 Kbps after hitting the fair-use threshold (typically 2 GB/day). Verizon TravelPass has the same structure. T-Mobile Go5G includes 5 GB of high-speed data per billing cycle for international use, then throttles to 256 Kbps. None of these plans provide truly unlimited high-speed data in Japan. An eSIM on NTT docomo at $22.49 for 20GB gives you a clear data allocation at full speed. When it runs out, you can top up rather than being throttled to unusable speeds.

How do I unlock my T-Mobile phone for a Japan eSIM?

T-Mobile unlocks phones after 40 days of active service (the shortest major-carrier requirement). Contact T-Mobile at 611 or use the T-Mobile app: More > Device Unlock. Processing takes 24-72 hours. T-Mobile also auto-unlocks phones after the 40-day period in many cases. Check by inserting a different carrier's SIM or looking for the eSIM option in phone settings. Postpaid phones must have the full device paid off. Prepaid phones need $100+ in refills over 12+ months. Start the unlock request at least 7 days before your trip to Japan. An eSIM on NTT docomo costs $3.49 versus T-Mobile's throttled free roaming.

Does using eSIM hotspot drain battery faster in Japan?

Yes. Running a personal hotspot while on cellular data drains battery 2-3x faster than normal use. Expect 3-5 hours of hotspot use before needing to charge (versus 8-12 hours of normal phone use). The phone maintains both the cellular connection to NTT docomo and the WiFi broadcast to connected devices, doubling radio usage. Bring a portable battery pack or keep your phone plugged in while tethering. On iPhone, battery optimization (Settings > Battery > Battery Health > Optimized Battery Charging) helps but does not prevent rapid drain. Factor battery into your Japan travel kit alongside the eSIM at $3.49.

What do I do if I get a surprise roaming bill after visiting Japan?

Call your carrier within 48 hours of the charge appearing. AT&T (611), Verizon (800-922-0204), and T-Mobile (611) all have billing dispute departments. Identify the specific charge from NTT docomo in Japan, give your travel dates, and state clearly that the charges were unintentional. Most carriers offer a one-time courtesy adjustment. Have your itinerary and travel dates ready. The agent needs proof you were in Japan during the billing period. Dispute resolution typically takes 24-72 hours and appears as a credit on your next bill.

Does my phone roam when crossing the border into Japan?

Yes. Your phone scans for available carriers and attaches to NTT docomo automatically the moment it detects a stronger signal from Japan. This happens without any confirmation from you. AT&T International Day Pass activates instantly at that moment and charges $10 for the calendar day. Verizon TravelPass does the same. You do not need to open an app or make a call. The Day Pass triggers on a single background sync: an email push, a location ping, or an app update check. Enable Airplane Mode before crossing and install an eSIM at $3.49 to prevent automatic carrier switching.

If something goes wrong

eSIM troubleshooting for Japan

Plan activated before landing

If you activated your Japan eSIM before landing, it may start consuming data before you arrive. Keep the eSIM profile toggled off in Settings until you land at Narita (NRT) / Haneda (HND). Activate it only after clearing customs to avoid using data before your trip starts.

No signal after landing (toggle airplane mode)

If the eSIM shows no signal after landing at Narita (NRT) / Haneda (HND), toggle airplane mode on and off. This forces your phone to re-register with NTT docomo's nearest tower. Wait 30 seconds for the registration to complete before checking connectivity.

Hotspot not working (enable on eSIM line)

Personal hotspot in Japan must be enabled on the eSIM line specifically. On iPhone: Settings > Cellular > select your eSIM line > Personal Hotspot ON. If hotspot is enabled globally but the data line is wrong, hotspot traffic routes through your home SIM's roaming connection.

Plan shows active but no internet

An active eSIM plan with no internet in Japan usually means the APN settings are incorrect. Contact your eSIM provider for the correct APN for NTT docomo. On iPhone: Settings > Cellular > Cellular Data Network > enter the APN your provider specifies.

Provider app shows data used but phone shows none

Discrepancies between your provider's dashboard and your phone's data usage counter in Japan are normal — carrier billing and device-side tracking update at different intervals. Trust your provider's dashboard for accurate remaining balance on NTT docomo. Phone counters reset with network settings changes.

Quick reference