Saily does not provide a truly unlimited high‑speed data eSIM for Japan. All plans marketed with the word “UNLIMITED” actually contain a fixed data allowance – for example, the Japan UNLIMITED 10 days plan gives 5GB per day and reduces speed to 1024kbps once the daily limit is reached, and the Global UNLIMITED 30 days plan offers 30GB for 30 days with the same speed reduction after the cap.
If a traveler wants unlimited high‑speed data they would need to choose a fixed‑data plan instead. For instance, the Japan 20GB 30 days plan offers 20GB for 30 days at $24.99 USD, and the Asia and Oceania 100GB 180 days plan gives 100GB for 180 days at $179.99 USD. These plans avoid downtime or speed throttling, though they have a defined data cap.