Jason Momoa has some tatoos, that's for sure. Some are fake, put on for show for the movies but a good number of them are real too. In Auquaman, he is covered in tats, by the suggestion of the director of the movie. He has one real life tatoo that was fairly recently put on which is in honor of his best friend who passed away in 2013. It is on his middle finger and reads "Diablo".
He also has his children's signatures permanently inked on his body. Jason definitely sports a good number of tats and some may be in spots we don't get to see so he has not said exactly how many he has and we just have to trust him on that questionable count. It is obviously for him to know and for his fans possibly to never find out.