The Tatau is an important element in Far Cry 3. After escaping Vaas' camp, Jason Brody wakes up to find Dennis giving him a tattoo on his left arm. Dennis tells Jason that he is a warrior and his Tatau determines who he is. The Tatau itself seems to be magical; as Jason grows stronger and wiser, the Tatau also enhances all of his physical abilities, most notably his strength, speed, stamina, intelligence, instincts & accelerates his healing speeds. The Tatau spreads across his arm by itself, with new elements burning into place with a glow of light. However, it cannot spread past a certain point unless a new 'base' is drawn by a Rakyat tattooist. There are three of these bases, with the first being the one Dennis applies in Amanaki Village. The second of these bases is also applied by Dennis, after Citra agrees to let Jason prove his worthiness to be a Warrior. The third base is applied by Citra herself, while Jason is unconscious, after undergoing the final challenge and defeating the mental Giant.
In gameplay terms, the Tatau actually reflects Jason's level. Every time he earns enough experience to earn a Skill Point, he can invest it in one of three different skill trees: the Heron, the Shark, and the Spider. Every skill earned causes a new piece of the Tatau to burn itself into existence on Jason's arm. The small dots that weave throughout the pattern are separate from the rest of the design; one dot is earned each time Jason finds and collects one of the 120 Relics scattered around Rook Island.
The tattoo used in Far Cry 3 is seen widely through south pacific Polynesian styles. The Samoan Pe'a is the most used decoration and meaning in the game, its mentioned by one of the Rakyat Warriors as a Malofire.
Other cultures such as New Zealander, Fijian, Tongan, Hawaiian, Cuban, and also Asian tattoo styles can be seen within the shark tattoo. The New Zealand Maori tattoo style is also seen on the Rakyat Warriors in the local population within the game. When a Rakyat Warrior ranks up he is given parts of what Dennis Rogers calls The Ta Moko.
- In the original trailers, Jason wore a wristwatch on his left arm and the Tatau was present on his right arm. It is believed the Tatau was switched to his left arm in the final game in order to make it more visible during gameplay, as Jason uses his left arm more prominently during animations to reload his guns.
- If the player possesses the Deluxe Edition of Far Cry 3, after the initial tutorial mission where Grant and Jason attempt to escape from Vaas' camp, Jason will suddenly have a full tribal sleeve tattoo on his right arm. This doesn't appear to be part of the Tatau, and is purely cosmetic.