Most leagues, yeah. In the US, It's allowed. Fuck, Tyson has a facial tattoo.

I boxed for several years, and I can tell you this- the reason most of them don;t have any, is they look up to legends like Rocky Marciano, Mohammed Ali, George Foreman, etc.. Tattoos just weren't as popular then..

My coach used to tell me "them things is like big signs sayin 'I can't fight, so I look pretty'".