The most numerous triathlon events are the sprint triathlon races. These races occur multiple times per year in most areas, even multiple times per month. They are the best races to get started as a first timer but also cater to elite athletes warming up for their long-distance events.
Generally, Sprint distance triathlons consist of a 750 meter swim, 20k bike, and a 5k run.
They are called sprints due to the faster paces that can be maintained over these shorter distances but just because they're short does not mean they can't be challenging. Sprint races can have choppy swim conditions, steep-grade bike climbs, sandy beach runs, cold rains, heat and humidity, and tough wind conditions.
With fair conditions Elites can complete an entire course in under an hour but don't worry if you're a first-timer because most races have generous cutoff times for the swim and bike legs. You should have plenty of time to complete the race and still enjoy the post-race party as an official finisher with your new triathlete friends!