According to Google, which I'm going on here:
|"Traditional Sak Yant (also called Sak Yan, or Yantra) tattoos are hand-etched onto the skin using ancient geometric designs mixed with Buddhist prayers. They are believed to give the wearer magic powers associated with healing, luck, strength, and protection against evil."
Because the tattoo contains Buddhist (pagan) prayers and are believed to give one magical powers, it would not be acceptable to have one.
- If one really believed that they had magic powers, it would constitute the sin of superstition.
- If one really trusted in the Buddhist prayers, it would constitute the sin of idolatry or at least sacrilege.
- If one liked the fear they induced in people, that would be the sin of pride.
- If one just liked the geometric designs, it could constitute the sin of scandal, in that others may think that you believe:
- in magical powers, or
- in Buddhism.
So overall it's probably a bad idea. It's important to think through your intentions and the implications of what you're doing. Ask yourself:
- What is my motivation?
- Why am I doing this, and why do I put importance on this tattoo?
- What might happen if went through with it?
- And, I might add, do I really want a piece of art permanently etched on my skin?
There are no prohibitions on tattoos per se in Catholicism, but there is the question of prudence and decorum to consider. Think of what you'll look like at 80 years old with the tattoo, what people will think — many people are turned off by tattoos.
Also consider what employment opportunities you could be ruling out.