If you've ever googled "unlimited eSIM" before a trip, you've probably seen the word plastered across half the providers in the market. Buy our plan, get unlimited data. Stream Netflix on the train. Tether your laptop. Tell your friends about it.
Here's the thing: in eSIM marketing, unlimited almost never means what you'd think it means.
What providers actually mean by "unlimited"
The technical term is Fair Usage Policy (FUP). It's a clause buried in the terms and conditions of nearly every "unlimited" data plan — eSIM, postpaid SIM, home internet — that says, in essence:
"You can use as much data as you want, until you use too much. Then we'll slow you down."
The threshold is usually somewhere between 30GB and 100GB per month, and the throttled speed is usually so slow that the connection becomes basically unusable for anything but text-based messaging.
A real example from the fine print
One of the largest "unlimited" eSIM brands on the market publishes the following in their terms:
"This eSIM includes unlimited data for the corresponding valid days. However, please note that the operator may reserve the right to apply a Fair Usage Policy. In particular, if the operator estimates the usage of more than 90GB of data in a month, they may temporarily reduce the speed to between 256-1024KB to avoid affecting other users."
Translated:
You get about 3GB per day at full speed (90GB ÷ 30 days). Past that, you get throttled.
The throttled speed is between 256 Kbps and 1 Mbps. That's roughly the gap between dial-up and slow 3G. Enough for WhatsApp messages, not enough for Google Maps to load reliably, video calls to hold, or anything Netflix-shaped.
The "unlimited" promise on the front page isn't wrong, exactly — it's just doing a lot of heavy lifting on the assumption you'll never read this paragraph.
The same page goes on to say: "If you think the local carrier has limited your speed, please get in touch with us by chat." In other words: the burden is on you to notice you've been throttled, contact support, and ask them to look into it. While you're abroad. With your throttled connection.
This isn't deceptive in the legal sense — the policy is published, in their own words, on their own site. They're just doing what most of the industry does, and most of the industry buries it deep enough that the average traveller never sees it.
Why providers do this
Two reasons, both legitimate:
Network capacity. Mobile networks are shared. A handful of users streaming 4K all day can degrade speeds for everyone in the same cell. Operators apply FUPs to prevent that.
Cost control. eSIM resellers buy data wholesale from the underlying carrier. If a customer pays $40 for "unlimited" and burns through 200GB, the reseller loses money on that order.
Throttling is the industry's compromise between the marketing word "unlimited" and the operational reality of finite networks. The problem isn't that throttling exists — it's that the disclosure is engineered to be missed.
How to spot a throttled plan before you buy
Search the page for "fair usage" — Cmd-F / Ctrl-F it. If the term appears, there's a cap.
Check the FAQ for "throttle" or "speed reduction". Honest providers will name the threshold (e.g. "5GB/day at full speed").
Read the terms & conditions — specifically the section on "data usage" or "service limitations." This is where the actual numbers live.
Watch out for soft language — "operators may reduce speeds," "fair usage may apply," "subject to network conditions." If a plan can't tell you a number, the answer is "yes, you'll be throttled, we just don't want to put it in the headline."
If a plan claims unlimited and the price is suspiciously low, the throttle is probably aggressive. Wholesale data has a real cost; nobody gives away truly uncapped data at consumer prices.
The alternative: capped plans with honest numbers
The other approach — which we use at Roamly — is to skip the word "unlimited" entirely and just tell you the actual GB you get.
A 20GB plan with full 4G/5G speeds the whole way through is, for most travellers on most trips, more useful than an "unlimited" plan that throttles after 30GB. You know exactly what you're getting, you can calculate whether it's enough for your usage, and there's no surprise slowdown midway through your holiday.
If you do run out, our reloadable plans let you top up in seconds — same eSIM, same number, no reinstall.
The takeaway
"Unlimited" in eSIM marketing usually means "unlimited until somewhere between 30 and 100GB, then aggressively throttled." That's not necessarily bad — for light users it's effectively unlimited, and for heavy users a generous capped plan often works out cheaper anyway. But you deserve to know before you buy, not after.
If you're shopping for a plan: read the fine print, search for "fair usage," and ask the provider directly if you can't find a number. Honest answers are a green flag.
Roamly is an Australian-owned eSIM provider with capped plans, transparent pricing in AUD, and live human support from Sydney. Browse plans →