How Much Mobile Data Do You Need for a Trip to Japan?

Most travellers to Japan need far less mobile data than they buy. If you mainly use maps, messaging and web searches, roughly 200–300 MB per day is a realistic budget, which puts a one-week trip near 2 GB and a two-week trip near 4 GB. Data use only climbs steeply when you add video — streaming, video calls and autoplaying social feeds are what turn a 5 GB plan into a 20 GB plan.

This guide builds a daily budget from figures published by carriers and by the apps themselves, then shows which plan size those numbers point to. Every consumption figure below comes from an official source listed at the end.

How much data does each app actually use?

The most useful published reference point is au (KDDI), which explains what one gigabyte buys. On its support page, au estimates that 1 GB covers about 6,600 web pages (calculated at 150 KB per page), about 2,000 emails (at 500 KB each), about 40 hours of LINE voice calling but only about 3 hours of LINE video calling, and about 18 hours of music streaming (at roughly 5 MB per track).

Video is the outlier. au calculates standard-quality video at about 4 MB per minute, which gives roughly 4 hours of playback per gigabyte, and 720p HD video at about 12 MB per minute — roughly 1.5 hours per gigabyte. au notes these are guidelines that vary with network conditions and content.

Netflix publishes its own numbers per hour of viewing, per quality setting. On its data usage page it lists Low as “up to 0.3 GB” per hour, Medium as “up to 0.7 GB”, and High as up to 1 GB for standard definition, up to 3 GB for HD and up to 7 GB for 4K.

Zoom publishes bandwidth rather than volume, so the per-hour figures below are converted from its stated requirements. Zoom lists 1.2 Mbps up and down for 720p HD in a one-to-one call, which works out to roughly 540 MB per hour, and 3.8 Mbps up / 3.0 Mbps down for 1080p, or roughly 3 GB per hour once both directions are counted. Audio-only VoIP is listed at 60–80 kbps, which is only about 27–36 MB per hour.

The pattern is clear before you do any arithmetic: text, maps and audio are cheap, and anything with moving pictures is expensive. A single evening of HD streaming can use more data than three days of ordinary sightseeing.

What about Google Maps — does navigation eat data?

Google does not publish a megabytes-per-hour figure for Maps, so treat any specific number you see quoted elsewhere with caution. What Google does document is the fix: you can download an area for offline use before you travel and navigate inside it without a connection.

That is worth doing for the neighbourhoods you will walk most. Google’s help page is explicit about the limits, though. Offline maps expire, and Google states that you must update any offline map you have downloaded before it expires. When a downloaded area is 15 days or less from expiry and you are on Wi-Fi, Maps tries to refresh it automatically.

There are two more catches. Google also states that offline maps cannot be downloaded in some countries and regions, listing contractual limitations, language support, address formats among the reasons — so check that your Japanese areas download successfully before you fly. And while offline, transit, cycling and walking directions are unavailable, which in a country where most visitors move by train and on foot is exactly the mode you wanted. Offline maps reduce your data use; they do not replace a connection.

How much data per day, by traveller type?

The daily figures below are estimates built from the per-activity numbers above. They are arithmetic, not measurements, and your own use will vary with how heavily your apps autoplay video in the background.

Multiply by trip length and the plan sizes fall out on their own.

One caveat worth stating plainly: these ranges assume you are on hotel or accommodation Wi-Fi in the evenings for large downloads, app updates and photo backups. If you plan to back up a fortnight of photos and video over mobile data, add several gigabytes on top and size up.

Should you buy 10 GB, 20 GB or unlimited for Japan?

Compare the tiers on cost per gigabyte rather than on headline price. Prices below are taken from the providers’ own Japan plan pages and are current as of August 2026; eSIM pricing changes often, so check the page before you buy.

Read the unlimited plan carefully. Ubigi’s Japan unlimited plan, priced at US$65 for 30 days as of August 2026, includes 60 GB of full-speed data under its fair use policy, after which the connection is “optimized to 2 Mbps” for the rest of the validity period. That is still usable for maps and messaging, but it is a cap with a soft edge rather than no cap at all.

Set against the 25 GB plan at about $1.28 per gigabyte, US$65 only starts to look like value somewhere above roughly 50 GB of actual use. Very few two-week sightseeing trips get near that unless you are streaming heavily every night or tethering a laptop for work.

Both providers also state which Japanese networks they use, which matters more than the logo on the app. Ubigi’s Japan plans list KDDI and NTT Docomo with 4G and 5G, and say data sharing is allowed. Airalo’s Japan packages are data-only and list SoftBank among the networks used.

A simple rule of thumb

• Choose 5–10 GB if you are sightseeing for a week or two and using maps, messaging and search, with Wi-Fi in the evenings.
• Choose 20–25 GB if you post to social media daily, make regular video calls, or travel as a couple sharing one hotspot.
• Consider unlimited only if you are working remotely over the connection, tethering a laptop for hours, or streaming video every evening away from Wi-Fi.

Buying one tier below what you expect to use is often cheaper than buying one tier above, because both providers sell top-ups. Running out mid-trip is an inconvenience, not a disaster — but only if you can still reach the app store or provider app, which is why some travellers keep a small buffer rather than cutting it to the last megabyte.

How can you make your data last longer in Japan?

The single biggest lever is video quality, because that is where the gigabytes are.

YouTube lets you set a default quality separately for mobile networks and for Wi-Fi. Its help documentation lists four options. Auto changes to give you the best experience for your conditions. Higher picture quality uses more data, so videos may take longer to start, with more buffering. Data saver gives lower picture quality, but videos may start faster. Advanced lets you pick a resolution manually.

Netflix offers the same control. Its data usage settings are changed per profile: open your Account page, choose Profiles, pick a profile, then open Playback settings. Dropping from High to Medium takes an hour of viewing from up to 3 GB down to up to 0.7 GB. On mobile, Netflix also offers a Save Data option it describes as letting you watch about 6 hours per GB.

Beyond that: download offline map areas for the districts you will explore, download episodes and playlists on hotel Wi-Fi rather than streaming on the move, switch video calls to audio-only when the picture is not adding anything, and turn off automatic photo and video backup until you are on Wi-Fi.

Frequently asked questions

Is 10 GB enough for two weeks in Japan?

For maps, messaging, search and light social use, yes — that profile lands around 4–7 GB over 14 days on the estimates above, leaving headroom. It is not enough if you stream video most evenings away from Wi-Fi or tether a laptop for work.

How much data does Google Maps use for a day of sightseeing?

Google does not publish a per-hour figure, so no honest answer gives you an exact number. Map traffic is small compared with video, and downloading offline areas in advance reduces it further — just remember that offline maps expire and that walking and transit directions are unavailable while offline.

Does an unlimited Japan eSIM really mean unlimited?

Not in the way the word suggests. Ubigi’s Japan unlimited plan documents 60 GB of full-speed data before the connection is optimized to 2 Mbps for the rest of the validity period. Always look for the fair use policy on the provider’s own page rather than the marketing headline.

What uses the most data on a trip?

Video, by a wide margin. Netflix on High in HD is listed at up to 3 GB per hour and 4K at up to 7 GB per hour, while music streaming runs around 18 hours per gigabyte and voice calls over LINE around 40 hours per gigabyte, according to au.

Can I top up if I run out mid-trip?

Both providers referenced here sell additional data through their own apps, and Ubigi states that its plans can be topped up through the app without needing remaining credit or Wi-Fi. Check the specific plan page for your provider before you rely on it, and leave yourself a small buffer rather than running the balance to zero.

The short version

Budget 200–300 MB per day if you are a maps-and-messaging traveller, around 1 GB per day if you post to social media and make video calls, and several gigabytes per day only if you stream. For most one- and two-week trips that means a 5–10 GB plan is sufficient and a 20–25 GB plan is comfortable, with unlimited making financial sense only above roughly 50 GB of genuine use.

Sources

• 1GBのデータ通信量で利用できる目安を知りたい (Data usage guide for 1GB) — au (KDDI) (accessed 2026-08-19)
• How to control how much data Netflix uses — Netflix Help Center (accessed 2026-08-19)
• Zoom system requirements: Windows, macOS, Linux — Zoom Support (accessed 2026-08-19)
• Download areas & navigate offline in Google Maps — Google Maps Help (accessed 2026-08-19)
• Change the quality of your video — YouTube Help (accessed 2026-08-19)
• eSIM Japan 10GB data – 30 days — Ubigi (accessed 2026-08-19)
• eSIM Japan 25GB data – 30 days — Ubigi (accessed 2026-08-19)
• eSIM Japan Unlimited data – 30 days — Ubigi (accessed 2026-08-19)
• Japan eSIM packages — Airalo (accessed 2026-08-19)