Not the best experience with Airalo in Japan. Needed 1GB to top up some extra data after I went through my TMO 5GB allotment (scam warning: TMO does not align the 5GB to your billing cycle, but rather a separate cycle that runs from the first day you begin using data outside North America).

Added the e-sim, was easy enough, but the data just randomly stopped working and I had to turn airplane mode off/on to reset it. Had to do it about a dozen times over 24 hrs. When it did work, it was very slow, no where near LTE or 5G speed.

Maybe their roaming partners in Japan are not the best, but it was an experience I probably won't be looking to repeat next time.