As a triathlete, there are a few common questions I routinely get from people who aren't familiar with the sport. Here is a sampling:
What's the order of a triathlon? Is the order always the same? Can you do it with a team? Do you swim in the ocean? Are you afraid of sharks? Have you done Hawaii? What's your favorite leg of the race?
But the most common questions are around the distances. People want to know how long the race is, and they don't understand that there are different triathlon distances. Below is a simple way to break it down.
Sprint Distance
The sprint distance triathlon is the most common triathlon you will find, and the shortest. A typical sprint distance triathlon consists of a 400 to 500 yard swim, 12 to 15 mile bike, and usually a 5k run.
Olympic Distance
The Olympic distance triathlon is a 1.5k swim (.9 mile), 40k bike (24.8 miles), 10k run (6.2 miles). This is the same distance used in the Olympics. You will also hear this distance referred to as the "International" distance, because that was what it was called prior to triathlon becoming an Olympic sport in 2000. Either name works just fine.
Half Ironman Distance
The half Ironman triathlon is a 1.2 mile swim, 56 mile bike, and a 13.1 mile run.
Ironman Distance
The Ironman triathlon is a 2.4 mile swim, 112 mile bike, and a 26.2 mile run.
Last thing to note, Sprint and Olympic distance events are often referred to as short course races, and the Half and Full Ironman distance races are referred to as long course races.