Unlimited eSIM for Japan: 10Mbps or Full Speed?

What matters before you choose

Full-speed unlimited has no separate tethering allowance, so a second phone or a laptop draws on the same unlimited data your phone does. Seven days is A$35.95.

Unlimited 10Mbps runs at up to 10Mbps the whole way through and carries a tethering allowance of 6GB across a seven-day plan. Seven days is A$24.95.

So: if you are sharing, buy full-speed. If you are not, 10Mbps is eleven dollars cheaper and ten megabits is more than most people need.

If your trip fits within 10GB, the fixed 30-day plan at A$19.95 costs less than either seven-day unlimited option. The arithmetic is below.

What each plan actually is

Neither plan has a set GB threshold or routine usage-based reduction in the supplier terms. Exceptional network-integrity measures may still apply during emergencies or for malicious or abusive use.

That is an unusually strong position and we have set it out against the rest of the category, including the providers who publish better numbers than we used to, in what unlimited actually means.

The difference between the two plans is what the ceiling is made of.

On Unlimited 10Mbps, the plan-level ceiling is up to 10Mbps throughout. There is no usage-triggered reduction in the supplier terms. Maps, messaging, calls and some HD playback can work when the connection sustains the needed speed. Large uploads and 4K video may take longer; laptop work also has to fit within the separate tethering allowance.

On full-speed unlimited, there is no plan-level speed cap at all. What you get depends on the network where you are standing.

Prices

Unlimited 10Mbps, three to ten days.

Full-speed unlimited, three to thirty-one days. No separate tethering allowance on any of them.

Best value per day on full-speed is the 26-day plan at A$3.88 a day. On 10Mbps it is the 7-day at A$3.56.

The tethering difference, in plain numbers

Full-speed unlimited has no separate tethering allowance. A second phone or a laptop draws on the same unlimited data your own phone does, which makes it the strongest sharing plan we sell for Japan.

Unlimited 10Mbps gives you a tethering allowance across the whole plan rather than per day, working out near 0.86GB a day on a seven-day plan. That is the same whole-plan allowance SimCorner publishes at the matching Japan durations. It is in the same territory as Holafly’s 1GB-a-day sharing cap, a material limit for couples and laptop users.

What 6GB covers depends on the connected device and settings. A laptop synchronising files or updating apps can use it faster than maps and messages on a second phone. Check the connected devices’ mobile-data settings before sharing.

If two of you are travelling on one plan, or a laptop is riding on your phone, consider full-speed. Eleven dollars more on a seven-day trip buys the supplier-backed plan with no separate tethering allowance. The supplier has not published a connected-device count.

Against SimCorner

They sell the same kind of Japan unlimited supply and they are the closest Australian comparison.

At these matching durations, we are cheaper at four, seven, ten and fifteen days; SimCorner is cheaper at thirty-one days. Their prices were rechecked on 14 September 2026 and both stores can change them.

Three things to know before you buy

Start it within 60 days of purchase. The unlimited range runs on a sixty day activation window, so buying within a month or so of departure suits it best. Some fixed-data Japan plans have longer start windows; check the selected variation.

The QR code is designed to be scanned once. Install it on the phone you are travelling with and leave it there, since it cannot be moved to a second handset afterwards.

Check the Japan refund position before buying. Our published refund policy offers a discretionary review for an unused, uninstalled plan when you contact us within 30 days; it does not promise an automatic change-of-mind refund. The supplier cannot reverse an issued Japan plan. Australian Consumer Law rights remain unaffected.

These plans are data-only. There is no number for calls or SMS, so keep your Australian line switched on with its data roaming off if you need to receive bank codes. We wrote that up in keeping your Australian number.

Choose the current duration and check its exact terms on our Japan eSIM product page.

Which plan fits your trip

Four to eight gigabytes is a useful planning range for a week of maps, messages and browsing. If that resembles your usage, a fixed plan is the better buy. Our Japan 10GB plan is A$19.95 and runs for thirty days. Seven days of full-speed unlimited is A$35.95, and seven days of 10Mbps is A$24.95.

Put another way, the money you would spend on a week of full-speed unlimited buys 20GB of fixed data instead, which is more than most people use in a fortnight.

Unlimited is the right call when your trip is one of these. Working off the plan. Sharing it with a partner or a laptop. Uploading photos or video daily. Long train journeys as the shape of the whole trip. If that is you, the no-threshold terms are worth more than the price difference, and we sell both so you can pick.

Related guides

Read more on sharing one connection, working away, daily uploads and long travel days. The category-wide terms are in what unlimited means.

Questions people actually ask

Which Japan unlimited plan should I buy?

Full-speed if you are sharing the connection or doing anything upload-heavy. Unlimited 10Mbps if the plan is for one phone doing ordinary things, because it is eleven dollars cheaper on a seven-day trip.

Is there a data cap on the Japan unlimited plans?

Our supplier terms state there is no set GB threshold or routine usage-based reduction on either Japan family. The 10Mbps plan is capped on speed rather than volume. Exceptional network-integrity measures may still apply during emergencies or for malicious or abusive use.

Is 10Mbps fast enough?

It can cover maps, messaging, calls and some HD playback when the network sustains the rate. Large uploads and 4K video take longer, and laptop sharing is subject to the plan’s tethering allowance.

Can I use a hotspot on the Japan plans?

Yes on both. Full-speed has no separate tethering allowance. Unlimited 10Mbps gives you 2GB across a three-day plan rising to 9GB across a ten-day plan, which works out near 0.86GB a day.

How long do I have to activate it?

Sixty days from purchase. That is shorter than several of our older plans.

Can I move the eSIM to another phone?

No. The Japan QR code installs once and cannot be transferred or rescanned after deletion.

Does it include a phone number?

No. All of these are data-only. Keep your Australian line on with data roaming off if you need SMS.

Sources

Our own plan terms are from the supplier product terms bound into our catalogue on 10 September 2026 and the live Japan plan selector, read 14 September 2026. SimCorner prices and hotspot allowances are from its Japan unlimited product page, checked 14 September 2026. YouTube’s playback guidance gives 5Mbps as a recommended sustained rate for HD 1080p; actual playback depends on the connection.

Written by Lachlan, who runs The SIM Shop from Brisbane and answers the support email himself.