In the last 10 years there has been a tremendous increase in the popularity of the sport of triathlon. Increased attention on the sport has brought about better equipment and products for triathletes. There's also been a change in the staple clothing item worn at a race. During my early years in triathlon when you stood at the start line of a swim and looked around you, almost everyone was wearing a speedo. The "Speedo" was the thing to wear. If you watched the yearly broadcast of the Ironman triathlon in Hawaii all of the pros were wearing speedos. Amateurs too raced in their speedos for the swim, bike and run. I wore a speedo for my first 25 triathlons. They even had speedos with a bike pad. Fortunately speedos have disappeared from my wardrobe and the wardrobe of virtually every other triathlete. Here are some reasons why this switch has been a positive change for the sport.
1) Let's be honest. Regardless of how well-chiseled your triathlete body is...Bottom line...no one wants to see you in a speedo. There is nothing worse than the guy setting up transition and walking around prior to the start of a race with nothing on but an old faded speedo. No one wants to see that much skin. Plus it's a bit awkward having a prerace conversation with a stranger standing there in his speedo.
2) If you have worn a speedo for any length of time you have experienced chafing. Due to the repetitive motion of cycling and running the inner thighs are very prone to chafing. Most athletes figure out what clothing works best for them and eliminate this issue, but the speedo did not give you many options to avoid the "chafe". You could try putting vaseline on your legs or some other kind of body glide but that usually wore off quick. Basically if you are prone to chafing the speedo is the worst thing to wear. There is nothing worse than training hard for months for an event and then have your race ruined by a severe chafe. Thank goodness for tri-shorts. I have never had an issue with chafing since I made the switch. Even if you are one of the lucky ones and don't chafe with a speedo..if you are still wearing one maybe you should consider switching to tri-shorts as well. We will all appreciate it!! 
3) Wearing a speedo with a bike pad made cycling a lot more comfortable. Unfortunately when wet, the pad became soaked and would not dry until you were on the bike. Because of this, every time you ran from the swim to T1 it looked like you had a wet diaper on. Not very attractive. It was even worse if you went for a warm-up swim and then had to walk around with your wet diaper look prior to the race. Not cool.
4) Last but not least, the speedo looks good on the top 1% or less of the people on this planet. Not only do you need the right body but you also have to ensure you have been tanning, shaved properly, etc. Unfortunately, back in the day when the speedo was the "uniform" for a triathlon, 95% of triathletes chose to wear one. It really wasn't good.
The sport of triathlon has changed quite a bit since I completed my first event in 1990. We have better bikes, aero equipment, training plans, etc. One could argue one of the best changes to the sport was the introduction of tri-shorts. Not only did this almost completely eliminate the issue of chafing but it also improved triathlon fashion considerably. If you are one of the last triathlete holdouts still wearing a speedo please consider upgrading to the tri-short
