More and more people are looking for a Sim Only plan with unlimited internet. But what does 'unlimited' actually mean in practice, and what should you check before switching?

In this article we explain how unlimited internet works, what the fair use policy involves, and who it's worth it for.

What does 'unlimited' actually mean with Sim Only?

'Unlimited' sounds literal, but in practice it usually works through a generous data allowance that resets daily. You get a fixed amount of data at full speed each day; once you use it up, you often top up for free, or a fresh allowance simply starts the next day. That makes it feel unlimited, without there being literally no limit at all.

How does the fair use policy work?

The fair use policy sets the conditions under which you can use unlimited internet. For most providers, this comes down to a daily limit that ranges from roughly 4 to 20 GB, depending on the provider. Importantly, with many plans your speed doesn't drop after that — instead you top up for free, or the counter resets the next day at full speed.

Fair use also means the plan is intended for normal smartphone use, not as a replacement for your fixed home internet. EU roaming usually has its own, lower limit too, separate from your domestic data allowance.

Who is unlimited internet worth it for?

  • You stream a lot of music or video on the go and regularly run into the end of a fixed allowance.
  • You regularly use your phone as a hotspot for a laptop or tablet.
  • You don't want to keep track of how much data you have left.

What are the downsides and things to watch for?

  • Unlimited internet is usually more expensive than a plan with a fixed, smaller data allowance.
  • 'Unlimited' differs per provider: always check the daily limit and conditions before choosing.
  • Not every provider actually offers genuinely unlimited internet, even when it's sometimes suggested.
  • EU roaming often falls outside the unlimited allowance and has its own, lower limit.

One example: Does Youfone offer unlimited internet? Explained & alternatives shows that not every provider answers that question with 'yes' — so it pays to check this per provider.

Unlimited internet or a fixed data allowance?

If you use less than about 20 to 30 GB a month on average, a plan with a fixed data allowance is usually cheaper. If you consistently go over that, or you simply don't want to keep an eye on your usage, unlimited internet is worth considering.

Want to jump straight to the best price? Read also: Cheapest unlimited internet Sim Only: how to find the best deal

Conclusion

Unlimited internet with Sim Only almost always means, in practice, a generous daily data allowance with a fair use policy — not a literally boundless bundle. Check the daily limit and conditions per provider before switching, and weigh up whether your usage actually needs it.

Still not sure? Give Welli 2 minutes and you'll get advice that fits your situation and budget.