Charlie (as well as the actor who portrays him) bears a tattoo on hisa tattoo on his left shoulder which reads "Living is easy with eyes closed"left shoulder which reads "Living is easy with eyes closed". This is a quote from The Beatles' song "Strawberry Fields Forever"Strawberry Fields Forever," a song whose lyrics and/or meaning could be considered symbolic of the Losties' experiences, Charlie's in particular. For further dissection of "Strawberry Fields Forever," see its Songfacts page.
Charlie is seen in "Walkabout" to have a tattoo of the Quenya symbol for "nine," a fictional language from J.R.R. Tolkien's Middle-earth cosmology. Dominic Monaghan got this tattoo after playing Merry in all three of Peter Jackson's Lord of the Rings films, as did the eight actors who portrayed the other members of the Fellowship of the Ring.