Going to japan in a couple weeks...but wanna get a tattoo?

i'm going on a class trip to japan in a couple of weeks and i really want to get a tattoo soon. i heard on a t.v. show that in japan getting a tattoo is somewhat of a taboo and some places don't allow tattoos. i really want to get one but i'm worried that i won't be able to participate in everything because of it. do a lot of places not allow tattoos, or should i just wait till i get back to get it?