Unlimited Data eSIM: What “Unlimited” Really Means
An unlimited data eSIM sounds like the end of watching your balance. Mostly it is. But almost every unlimited travel plan, ours included, gives you a set amount of full-speed data each day and then slows you down until the next reset. That's fine for some trips and a poor deal for others. Here is how it actually works, so you can tell which kind of trip yours is.
How an unlimited plan actually works
On Siima, an Unlimited plan gives you 1 GB of full-speed 4G/5G data every 24 hours. Once you've used that gigabyte, the connection drops to 512 kbps for the rest of the 24-hour window. Then the allowance refills and you're back at full speed. This repeats every day for as long as the plan runs.
There's no total limit and the eSIM never gets switched off. The only thing that changes is speed. That is the honest meaning of “unlimited” across most of the travel eSIM market. The daily threshold and the slowed speed vary by provider, and some put those numbers in the terms of service rather than next to the price. We show ours on the plan card and again at checkout.
The 24-hour clock starts when the eSIM first connects to a network. Land in Lisbon at 9 pm, switch on, and your full-speed day runs 9 pm to 9 pm for the whole trip. Worth knowing if your heavy use is in the evening: you could burn the gigabyte on hotel-room streaming at 11 pm and spend the next day's sightseeing on the slow lane until 9 pm.
What still works at 512 kbps
512 kbps is slow by 2026 standards, but it isn't useless. It's roughly what a decent 3G connection felt like. Text-based things carry on almost as normal. Anything that streams video doesn't.
| What you're doing | At 512 kbps |
|---|---|
| WhatsApp, iMessage, Telegram texts | Fine. You won’t notice much |
| Fine, attachments take a little longer | |
| Google Maps and navigation | Works. Map tiles load slower in a new area |
| Uber, Grab, Bolt and similar | Works |
| Sending photos | A few seconds each |
| Browsing news or booking sites | Slow but usable |
| Instagram and TikTok | Frustrating. Video buffers constantly |
| Video calls, Netflix, YouTube | Not realistic |
So an unlimited plan works as a safety net. After the full-speed gigabyte is gone you can still find your way back to the hotel, answer messages and call a car. You just can't watch anything.
How far does 1 GB a day go?
Further than people expect, as long as video stays out of it. A day of maps, messaging, a few dozen photos sent and some browsing usually sits well under a gigabyte. Social feeds are what eat it. Half an hour of Instagram Reels or TikTok can use a few hundred megabytes on its own.
If you're not sure where you land, the data usage calculator adds it up app by app. Keep phone backups and app updates on WiFi only, too. A photo library syncing over mobile data will clear the day's allowance before breakfast.
Unlimited or fixed GB: which to buy
Our fixed-GB plans work differently. Every gigabyte runs at full speed with no daily cap, and when the data is used up the plan stops rather than slowing down. You can top up any time. Neither type is better in general. It depends on how you use your phone.
Both types show the full price before you pay: plan cost, a small service fee and card processing listed separately, and no app to download first. Compare the two for your destination and pick whichever works out cheaper for the way you actually travel.
Unlimited plans and hotspot
Sharing an unlimited plan with a laptop is where the daily cap bites hardest. A laptop pulls OS updates, cloud sync and browser tabs in the background, and it can get through a gigabyte in well under an hour. After that, every device on your hotspot shares 512 kbps.
For the odd email from a café, fine. For a remote-work week, buy a fixed-GB plan big enough for the job. The hotspot and tethering guide explains how to check a plan allows tethering and how to stop a laptop eating the allowance.
Comparing unlimited plans between providers
The price is only half the comparison. Before buying any unlimited eSIM, find three numbers: how much full-speed data you get per day, what speed you drop to afterwards, and whether the allowance resets daily or only once for the whole plan. A plan that throttles to 256 kbps is noticeably worse than one that throttles to 512 kbps, even if the daily allowance is the same.
Holafly is the best-known flat-price unlimited provider, and we compare how its fair-use policy differs from per-GB pricing in Siima vs Holafly. If a provider won't tell you these numbers before checkout, treat that as your answer.