When I was planning a trip to Japan, I didn't want to run around the airport looking for a SIM card. I learned about Mobal eSIM beforehand https://www.mobal.com/japan-esims/ and decided I'd give it a try. It's really simple—I connected it at home, and the internet worked right away upon arrival. It works reliably, even on the subway. It's convenient that you don't need to plug anything in. Just turn it on and go for a walk. No stress and no surprises, just the way it should be.