Generally, beginner triathlons are Sprint Distance, which involves a 750m swim, a 20km cycle and a 5km run. This is recommended for those looking to get their feet wet and sample the sport. The next stage is an Olympic Triathlon, which is a 1.5km swim, 40km cycle and 10km run. The decision between a sprint or Olympic triathlon will depend on your personal fitness level and goals. If you're new to triathlons and looking for a more manageable goal, a sprint triathlon may be a good place to start. However, if you're an experienced athlete looking for a greater challenge, an Olympic triathlon may be more suitable. Ultimately, the best choice will depend on your individual circumstances and level of fitness.