You may need an embassy visa for Japan if you have a Thai passport
Visa options for Japan
Visitor visa is required for trips longer than 15 days
Travelers need a visa to visit Japan for Business or Tourism for more than 15 days. Travelers do not need a visa if staying for 15 days or less. Travelers must have an ePassport in compliance with ICAO standards. A paper or embassy visa is the only visa available for travelers visiting Japan. The visa is typically a stamp or sticker added to the passport. Travelers must obtain this visa from a local embassy, consulate or visa center before traveling.
This is not offered by sherpa°.
Apply on the government site.