Competing in each of swim, bike and run separately can do wonders for your multisport game. When you compete in the three sports individually there is less pressure and you can experiment with how hard you can push in that sport specifically. It will also give you a taste of that sports individual culture and energy, which will give you more confidence in that sport.
Masters swim meets are abundant across the globe. There are plenty of opportunities for you to jump into a Masters swim meet and build up your tolerance for hard swimming. Racing usually forces you to a new level of effort and that in itself serves as a great workout. Swim meets have all distances from 50 meters to 1500 meters and you should experiment across all of the distances not just the long ones. If you did not grow up doing swim meets then this will likely make you feel out of your element but that is a great way to learn and you will definitely benefit.
Biking events require some courage if you have never raced a bike. If you are doing non drafting events your best bet is to find a local group that hosts a weekly time trial. This is a great opportunity for you to get a great workout as well as test some of the aero equipment you only really get to pull out on race day. Time trials on the bike allow you to experiment with your power output over shorter distances and how you are going to generate that power. Time trials also help you improve your tolerance for harder efforts on the bike. If you are doing draft legal racing find some criterium events to participate in. In cycling you must be registered and assigned a category so you are racing against athletes of similar skill and fitness. Criterium racing is vastly different to time trialling and is an essential type of race to practice if your multisport races are running this format. If your key races in multisport include draft legal racing you should be doing some criterium riding on a weekly basis to fine tune your abilities and understand the dynamics of pack riding.
Running races are simple and cost effective. You don’t need much to jump into a running race and there are literally thousands of events across the globe every year. You don’t need much equipment so you don’t even have to be that organized to jump into a running event. Running hard against runners will fine tune your understanding of pacing and will help you learn to really dig during the run portion of a multisport race. Running races also help you increase your tolerance for hard running, which is essential if you want to be tough and strong in the last third of a multisport event.
When you are building out your competitive multisport season consider including some competitive events in each of swim, bike and run prior to your first multisport events to up your game in the multisport department.