Unlimited vs fixed data eSIM: which is better for your trip?

A fixed-data eSIM gives you a set number of GB for a set number of days: 10 GB for 30 days, say. An "unlimited" or daily plan gives you a high-speed allowance every day, 1 GB or 2 GB for example, then slows you down until the next day's reset. For most trips a fixed plan costs less and is more flexible, because you can use a lot one day and very little the next. Daily plans make sense when your usage is heavy and steady, and when you'd rather be slowed down than run out. Cabin Mode sells both kinds, and prices in this post come from its catalog, checked 25 September 2026, in USD.

How a fixed-data plan works

You buy an allowance and a validity period. Both count down from when the plan starts: the first network connection at your destination for most plans, installation for a few. The plan screen says which.

• Use the data however you like. 3 GB on day one and 100 MB on day two is fine.
• When the GB run out, the line stops carrying data. You can top up; in Cabin Mode, top-ups add data to the same eSIM.
• When the validity ends, the line stops, even with data left over.

Bigger plans cost less per GB. In Japan, for example:

Prices checked 25 September 2026. The app shows them in your own currency, with the per-GB figure on every fixed plan. See all Japan plans.

How "unlimited" and daily plans work

Most travel eSIMs marketed as "unlimited" are really daily plans with a fair use policy. The pattern is the same across the industry:

1. You get a daily high-speed allowance: 500 MB, 1 GB, 2 GB, 3 GB, 5 GB or 10 GB a day.
2. Once you've used it, your speed is throttled for the rest of that day. You stay connected, just slowly.
3. The allowance resets roughly every 24 hours. Depending on the network, that's 24 hours from first connection or local midnight on the operator's clock.

What "slowly" means matters a lot:

In the Cabin Mode app, daily plans show the per-day allowance as the headline (for example, "1 GB/day"). Plans labelled FUP1Mbps slow to 1 Mbps after the daily allowance, which is enough to keep most things working. Other daily plans may slow further, to a few hundred kbps, until the reset.

A few more things about daily plans:

• Unused allowance doesn't roll over. A quiet day's leftover GB is gone at the reset.
• A top-up doesn't lift the daily cap. On daily plans, a top-up generally adds days at the same allowance. It won't restore full speed if you've already been slowed that day.
• There's no honest per-GB figure, which is why the app shows one for fixed plans only.

The price comparison

Take a 10-day trip to Japan at about 1 GB a day, which is typical for a first visit (why):

The same shape shows up elsewhere. In Italy, 10 GB for 30 days is $8.56 and the 1 GB a day plan is listed at $1.08 a day. In the United States, 10 GB for 30 days is $13.26 and 1 GB a day is $1.50 a day. Italy plans, United States plans.

So, on price alone, a fixed plan sized with a little headroom usually beats a daily plan for the same total. The case for daily plans is about behaviour, not price.

When a fixed plan wins

• Your usage is uneven. Heavy on travel days, light on beach days. A fixed pool absorbs that; a daily cap wastes the light days.
• You're mostly on Wi-Fi. Hotels, cafés and trains with Wi-Fi mean you only need mobile data for maps and messages. A small fixed plan covers it.
• The trip is longer than a week or two. Fixed plans with 30 days or more of validity are cheap per day. Some destinations have 90- or 180-day options.
• You want to know the total up front. One price, one allowance.
• You might come back. A fixed plan with validity left can be reused on a return trip. See can you reuse a travel eSIM.

When a daily or "unlimited" plan wins

• Heavy, steady use. Video calls every evening, streaming on long train rides, uploading footage. A 3 GB or 5 GB daily allowance can be easier than guessing a large fixed size.
• You'd rather slow down than stop. When a fixed plan runs out, data stops until you top up. On a daily plan, especially a 1 Mbps one, you're still online, just slower.
• Short, intense trips. A long weekend where you know you'll use a lot.
• Working remotely on the road. If you're hotspotting a laptop, a generous daily plan protects you from one big sync eating the whole trip's data. Be aware that some operators restrict tethering on any plan; where we know of a restriction, it's on the plan screen.

Throttling and fair use on fixed plans

Fixed plans are usually full speed until the data runs out, subject to the local network. "Full speed" depends on the operator, the network generation listed on the plan (4G or 5G) and where you are. Operators also manage traffic at busy times and may treat travel eSIM users the same as their own prepaid customers. That's true of every travel eSIM, fixed or daily.

Fair use terms also cover how a plan is used. Using a travel plan permanently in your home country, for example, isn't what they're for, and operators can suspend lines used that way.

A simple rule

1. Estimate your daily use honestly: 0.5 GB light, 1 GB typical, 2 GB or more heavy.
2. Multiply by your days and add about 20%.
3. If a fixed plan of that size exists and you're a light or typical user, buy it.
4. If you're a heavy, steady user, or you'd hate being cut off, compare the daily plan price per day against the fixed plan and choose with your eyes open.
5. If you're between two fixed sizes, take the bigger one. It's usually cheaper than topping up later.

For multi-country trips, the same logic applies to regional plans. Regional vs country eSIM covers that choice.

Frequently asked questions

Is an unlimited eSIM really unlimited?

Rarely. Most "unlimited" travel eSIMs give you a daily high-speed allowance, then slow you down until the next reset. You stay connected, but at anything from about 128 kbps to 2 Mbps depending on the plan.

What does FUP 1Mbps mean on an eSIM plan?

FUP is fair use policy. A plan labelled FUP1Mbps gives you a daily high-speed allowance, then limits you to 1 Mbps until the daily reset. That's enough for maps, messaging, music and standard-definition video.

Is it cheaper to buy a daily plan or a fixed GB plan?

For the same total data, a fixed plan is usually cheaper. In Japan, 10 GB for 30 days is $9.40, while 1 GB a day is listed at $2.00 a day (prices checked 25 September 2026).

What happens when my fixed data eSIM runs out?

The line stops carrying data. You can top up to add more data to the same eSIM, as long as the plan hasn't expired, or switch to Wi-Fi.

When does a daily eSIM allowance reset?

Roughly every 24 hours. Depending on the network, that's 24 hours after your first connection or at local midnight on the operator's clock.

Do I need unlimited data for a two-week trip?

Most people don't. A typical traveller uses around 1 GB a day, so a 15 or 20 GB fixed plan covers two weeks with headroom, usually for less than a daily plan.