nextSIM does not sell a truly unlimited data eSIM for Iceland. Every plan that carries “Unlimited” in its name, such as eSIM Unlimited Standard 1 Day Iceland or eSIM Unlimited Plus 1 Day Iceland, contains a fixed data cap of 1 GB (or 2 GB for the Plus version). Once the capped amount is reached the speed is reduced to 512 kbps, or 2000 kbps for the Plus plans.
If a higher data allowance is needed, nextSIM offers fixed data plans instead. For example, the eSIM 100 GB 30 Days Iceland plan gives 100 GB of high‑speed data, and the eSIM 50 GB 30 Days Iceland plan provides 50 GB. These plans are not unlimited, but they avoid the throttling that occurs after the smaller caps are exceeded.