Here are the most important rules to follow in triathlon. The rules at some events will vary, but for most non-draft, USAT sanctioned events, these will apply. Note that this is not a comprehensive list of all rules, it is simply a list of the most important ones to know. Always check the athlete’s guide for your particular race.
You CANNOT make forward progress aided by one of the volunteers or course marshals on kayak, long board, boat, etc. You CAN go up to one of those individuals and hold on to their kayak, long board, boat, etc. to take a break, catch your breath, adjust your goggles, and just float there. This distinction is good to know especially for triathletes that have discomfort with open water swims. You can rest!
No Drafting. Drafting occurs when one rider follows closely behind another rider. Riders are expected to maintain 5 bike lengths (age groupers) or 6 bike lengths (professionals) between them unless passing.
No Blocking. Blocking occurs when one rider rides next to another rider or when one rider rides on the left edge of the bike lane. Riders are expected to ride single file at all times except when passing. Riders are also expected to ride to the right side of the road so that faster riders can pass them on the left.
Realistically. In reality, when you’re in a race with a few hundred to a couple thousand other cyclists, there will be points when you simply can’t spread out. Don’t worry about getting a penalty there. As the race continues, the pack usually thins out and that’s when you need to pay more attention to drafting and blocking.
No music/headphones/phones. Runners are not allowed to carry phones with them or wear headphones to listen to music on any type of device. Pay special attention to this because it is different from most running road races like half marathons and marathons which generally now allow runners to wear headphones to listen to music.
These are just the key rules to be aware of. You can check USAT’s website for a complete listing of the rules and check with the specific race that you are participating in for more details.