Are there any onsens in Tokyo that allows tattoos?

Hi Jay, I hope you and your wife have a lot of fun in Japan. I found a similar question to your here: https://planetyze.com/en/japan/forum/japan/onsens-in-tokyo-that-allow-tattoos

maybe this will help:
Jakotsu-yu is not a real onsen, but it is a public bathhouse that uses onsen water in Asakusa. It allows people with tattoos, so it's popular with foreign tourists visiting the area. https://www.tripadvisor.com/Attraction_Review-g1066461-d1197818-Reviews-Jyakotsuyu-Taito_Tokyo_Tokyo_Prefecture_Kanto.html

There’s also an Onsen facility in Narita (Yamato-no yu) but not near the airport, which allows people with tattoos. http://www.yamatonoyu.com/eng/index.asp

Enjoy your trip! :-)