- "Triathlons bring three activities together in an epic way. In nature, it is doubtful you will be required to swim, bike, and run to escape the jaws of a bear or shark – but these days – the threat is your own ego and the darkness setting in as you grow older. The marathon was an ancient ritual popularized by the Greeks – like buggery – but combining exercise and ego is an American tradition."
- ―GTA V Website
There are a total of 3 Triathlons in GTA V. The first one becomes available after the mission Daddy's Little Girl, and the other two are unlocked as the player completes the previous thiathlons. Each character may run any of the triathlons, so long as they are unlocked. The Triathlons in GTA V are made up of Swimming, Cycling, and Running. They are a great way to boost the player's stamina. Medaling in all three events is required for 100% completion. The player receives no reward for completing the triathlons other than potential increases to stamina, strength, and lung capacity. Unlike the Beat the Cock! triathlons, the triathlons in GTA V may be accessed on any day, at any time of the day or night.
The opponents in GTA V's triathlons use a catch-up/rubberband AI system, meaning that they will regularly catch up on you or gain the lead momentarily regardless of your speed or tactics. On occasion however, especially in the Coyote Cross Country Triathlon, the system will glitch out and one or more opponents will receive a massive speed boost, shooting several checkpoints ahead of you. Do not let this fool you into thinking the race is lost, they will slow down during the final leg.
- The Vespucci Beach Triathlon is located on the beach of Vespucci. At least 60% Stamina is advised before competing in this event.
- The Alamo Sea Triathlon is located on Seaview Road in Grapeseed and is only unlocked after the completion of The Vespucci Beach Triathlon. It lasts about 7 minutes and is great for increasing player stamina.
- The Coyote Cross Country Triathlon is located on the south beach of the Alamo Sea at Marina Drive in Sandy Shores. This triathlon will last approximately 30 minutes and is unlocked after the completion of The Alamo Sea Triathlon. 100% player stamina is advised before entering this triathlon (this goes for the person holding the controller, too, as they will spend 30 minutes repeatedly pressing the buttons - This does not apply to the PS4 or Xbox One version since the player can enter first person mode and simply hold down the X or A button for the running/swimming parts only).
- Swim underwater for sections of the swimming part
- Put a elastic band around the X or A button (PS3 and Xbox 360) And hold the trigger in position, for the straight part of the race.
- For the running and swimming parts, Enter first person mode and hold X or A button (PS4 and Xbox One) for an easier method to speed up.
- Remember that the third and last triathlon (The Coyote Cross Country), will become unavailable for both Michael and Trevor, between the missions Minor Turbulence and Monkey Business. Because, since both of then are banned from Los Santos by Martin Madrazo during that time period, and the last part of that triathlon requires the player to enter Los Santos, that would cause a contradiction with the storyline.