There are generally 4 triathlon distances: Sprint, Olympic, Half-Ironman, and Ironman. So to help you with your triathlon race season preparation here's a quick peek at the pros and cons of each triathlon distance.
Pros - Imagine an overweight, sedentary individual sitting on the couch and licking Cheetos residue off their fingers. Technically, it would be possible for that person to be standing on the starting line of a Sprint triathlon just 12-16 weeks later. This is because since sprint triathlon distances are short, they have a low barrier to entry and don't require extensive physical preparation. You only need to be able to swim 400-600 meters (8-12 laps in a pool), ride a bicycle 10-15 miles, and run or walk 2-4 miles, and this requires continuously exercising for about 50 minutes to 2 hours. This may be tough for some, but it is do-able for most. Furthermore, if you're fit or experienced in triathlon, and you want to go faster in a Sprint triathlon, it will take less training time than the longer distances, so it's pretty rare for Sprint triathlon distance to be a family-wrecker.
Cons - Sprint triathlons don't carry much notoriety. You may become offended when someone asks you how your "Mini-Triathlon" went. And if you do decide to go fast or shoot for a podium spot, a sprint triathlon is going to hurt, a lot. You'll need to be at a red-hot high-intensity effort near maximum heart rate for about 2-3 times as long as a 5K run. That's a zone that's tough for most to get into, but the price you have to pay if you want to win or place in a Sprint triathlon distance. Another possible con for many is that you simply don¹t have much time to eat food during a Sprint triathlon, so those who compete in order to have access to a moving buffet of gels and cookies will be disappointed.
Pros - As the name implies, the Olympic distance is pretty much the same triathlon distance covered in the Olympics (1.5K swim, 40K bike, 10K run), so when someone asks you if you did a "Mini-Triathlon", you can respond by saying, "No, I did exactly what they do in the Olympics". This will probably make you feel good inside, and at the same time, you still don't have to train quite as much as the Half-Ironman and Ironman triathletes, so your spouse, kids, family, and friends will not find you a complete stranger. If you're a triathlon junkie, you can do a ton of Olympic distances races in a year, and not have a high risk of overtraining or injury, since they're relatively short and you'll recover quickly. Plus, you actually get to eat a little bit. Bon appetit.
Cons - At the same time, the intensity of your Olympic triathlon distance training will be far greater than the Half-Ironman and Ironman triathlon. So, similar to Sprint triathlon, you need to be willing to go into the pain cave far more often. If you're not fit, it's still possible to get roped into an Olympic distance triathlon by your peers, who will probably say something like, "C'mon, it's just 25% of an Ironman." When you reach the 5K point of the run, however, you will be planning revenge on these peers. And if you do want to get on the podium for an Olympic distance race, be ready to execute flawlessly, since the tiniest mistakes can cost you precious seconds that add up very quickly for this triathlon distance.
Pros - Congratulations, you know have bragging rights for having completed a triathlon distance that contains the word "Ironman", without actually having to give up your entire day. As a matter of fact, in many Half-Ironman events, you can be done by lunch, feel very good about yourself, and still have the rest of the day to make excuses not to mow the lawn ("C'mon, I just did an Ironman event!") or to go drink lots of cold beer. If you don't like the red-hot intensity of Sprint and Olympic distance training and racing, but don't have the time to devote to Ironman, then this triathlon distance is a nice compromise. Plus, you can travel long distances to race a Half-Ironman without the same type of race day stress as you experience in Ironman. Finally, if you make a mistake during a Half-Ironman race, such as remembering to poo halfway through the half-marathon, you'll still have lots of time to make up for those lost seconds.
Cons - With all the training and effort you you'll put in for a Half-Ironman triathlon distance, you'll sometimes find yourself asking the question, "Why didn't I just sign up for an Ironman?". After all, you're typically just as sore the next day after a Half-Ironman as an Ironman, and you still have to do lots of logistical race planning when it comes to hydration, electrolytes or food. Also, the "Half" part of "Half Ironman" doesn't lend itself quite as well to bragging rights ("You only did half of it? How come? Did you quit halfway through?"), but you'll sound desperate and boring trying to explain what a 70.3 is ("Well, a full Ironman is a 2.4 mile swim, 112 mile bike, 26.2 mile run, which is 140.6 miles, but what I've done...dude, wake up.")
Pros - It's Ironman, for crying out loud. This event has been elevated to tattoo-worthiness status. Did you hear me? You get to swim 2.4 miles, ride 112 miles, run a marathon, and then get a tattoo and your parents will still be proud of you. Heck, your boss probably will too. Unless you're a musician, Harley fanatic or artist, in what other social situations are tattoos acceptable? Even if you skip out on the tattoo, you'll have bragging rights for life, you'll feel very good about yourself, and you will get to eat over 4000 calories a day and stay skinny.
Cons - Ironman is a logistical nightmare. Not only do you need to squeeze 12-25 training hours into any given week, but you also need to figure out how to eat and drink while moving long distances without your gut distending like a swollen balloon or your fragile bodily sphincters crying out in distress. You will become best friends with your local sports medicine doctor and physical therapist, and this is not a good thing. During the actual race, you will go through periods that have been compared to childbirth, a death-march, and a "very dark place". When you finish, you may experience symptoms of post-traumatic stress disorder. You may forget what your boyfriend, girlfriend, husband or wife looks like, and you romantic times with them may involve nothing more than you lying like a sack of potatoes on the couch while they lovingly stroke their hands through your sweat-caked hair. You may have to appease them by allowing them to help you design your tattoo.