Choosing a plan
How "unlimited" eSIM plans work: FUP explained
4 min read · Updated September 16, 2026
"Unlimited" doesn't always mean the same speed the whole time. Depending on the product, the speed may be throttled after a certain amount of usage, or the network's fair use policy (FUP) may apply. Before buying, check the "high-speed data cap", the "speed after the limit", and when you can use high speed again.
What is FUP?
FUP (Fair Use Policy) is a policy that lowers your speed once you exceed a certain amount of usage, to keep network use fair. The high-speed data cap, the reference period, and the speed after the limit differ by product and network (and it isn't always per day). It's usually a slowdown rather than a complete cutoff, but how usable it stays depends on what the post-limit speed is.
It varies widely by provider
Even for the same "unlimited", the high-speed data cap, post-limit speed, and reference period differ by provider and product. Some don't disclose these figures at all.
How to check
- Check the product details for a "Fair use / FUP / speed limit" item
- Check the high-speed data cap and the reference period (whether it's per day, etc.)
- Check the stated post-limit speed; if there is none, treat it as "no information"
- Check whether tethering has a separate cap
Unlimited vs. fixed-amount: which is better?
If your daily data usage isn't high (mostly maps and messaging, within 1–2GB), a fixed-amount plan is often cheaper. Conversely, if your usage is high and hard to predict (tethering, video, etc.), an unlimited plan with a generous FUP cap is more relaxing.
FAQ
It's "unlimited", so why does it slow down?
The product's speed limit (fair use policy, FUP) may have kicked in. A congested area or weak signal can also be the cause, though, so check both your usage and the product's speed-limit conditions. The high-speed data cap and post-limit speed vary by product.
Where do I check the FUP cap?
Check the fair use / FUP / daily cap item in the provider's product details. If it isn't stated, treat it conservatively as "no information", and it's safer to choose a product that discloses the cap.
I only use a little data a day — do I need unlimited?
If your usage is low, a fixed-amount plan (e.g. 5–10GB total) may be cheaper. Unlimited is better when you use large amounts every day or your usage is hard to predict.