pretty much what goldengraemes said. Tattoos and tanning do not mix at all. Tanning often will fade your tattoo much quicker than it would normally. Some people put sunscreen on just the tattoo when they go tanning, but you will have to live with the skin around the tattoo being much paler than the surrounding tanned skin. If you arent willing to live with that, then dont get a tattoo.

And of course, tanning is bad for you with many health risks, etc.