Gym with tourist visa and tattoos

Hello! I'll be living in Fukuoka with a tourist visa for 3 months. I'd like to go to the gym for weightlifting and I'm wondering if it's possible without a Japanese bank account. Do they accept tattoos? Thank you!

You can be a member of Gold gym in Fukuoka.
Those whose tattoos fit within 15cm x 15cm are allowed to enter. However, it can be covered by supporters, shirts, taping, etc. to avoid exposure.

Thank you! Can you tell me something about JoyFit 24 too? I don’t speak Japanese very well but someone who does will come with me to help me with papers. Do you think that will be ok?

JoyFit 24 is among gyms refusing people with tattoos.
I checked several locations and their FAQ states:

Q: タトゥー・刺青があります。入会できますか ?
A: 申し訳ございません。JOYFITではタトゥー・刺青のある方のご入会はご遠慮いただいております。

What if I cover the tattoos and don’t show them at all?

As a general rule, activities that you would normally do in your country that usually require some form of contract or agreement, that's similar to Japan too. There may be exceptions with some companies offering short-term stays/rentals of facilities, though it really depends.

If you're serious to try and do activities like working out or other things that would require an agreement/bank account, I would honestly just try and apply to work in Japan if you're planning to stay here for so long. You have to remember, both the government and companies want to make money. If a foreigner is coming here just for a short stay, it's more risky on their part if they made a commitment to that foreigner as the person could just leave and not pay.

If you're serious to do these things, just look around online for companies that offer memeberships to foreigners who stay a short time, otherwise, most other companies like to see a bank-account or some assurance/collateral so you don't leave them high and dry.

On tattoos, Japan is still a little closed-off from the idea, despite some businesses accepting tattoos just because it's synonymous with Yakuza and other negative lights. I'd cover them up if you plan to do working out or onsen in Japan. Hope the info helps you.