Yes, MicroEsim offers unlimited data eSIM plans for Japan. The plans range in price from $2.13 USD for a 1‑day plan to $68.62 USD for a 30‑day plan, and the validity period varies from 1 day to 30 days. All of these plans are marked as unlimited data and are available on 5G networks in Japan.
Because the plans are unlimited, the data allowance is not capped, but speeds may be throttled after heavy usage. The maximum advertised speed is 10000kbps, and a Fair Usage Policy applies. If you need confirmation of the typical amount of data that can be used at normal speed or details about the throttling policy, you should contact MicroEsim directly.