Beginners' guide to swim events

When you signed up for your first swim event, it felt like aeons away. But now the big day's approaching and your stomach's full of butterflies, what can you do to prepare? From triathlon to distance swim, here's a practical guide to outdoor swimming events.

Entering a swim event is a great way to celebrate your outdoor swimming or work towards a goal. While some events are distinctly competitive, others are celebrations of outdoor swimming where the emphasis is on enjoyment. And many events help raise money and awareness of open water swimming.

Types of event

Events fall into two categories: swim events and multi-discipline events where you also run and/or cycle. Swimming events tend to attract swimmers (obviously!), but for a fair portion of those taking part in triathlon and aquathlon, swimming is their weakest discipline.


Swim then bike then run. You can choose from various distances (these may vary):

  • Super sprint: 400m (swim), 10km (bike), 2.5km (run)

  • Sprint: 750m (swim), 20km (bike), 5km (run)

  • Standard or Olympic: 1500m (swim), 40km (bike), 10km (run)

  • Half-Ironman: 1.9km (swim), 90km (bike), 21km (run)

  • Ironman: 3.8km (swim), 180km (bike), 42km (run)


Swim then run:

  • Sprint/pool: 400 or 500m (swim), 2.5km (run)

  • Open water: 750m (swim), 5km (run)

  • Long distance: 1.5km (swim), 10km (run)

Open water swim

This is any swim in river, lake or sea and can range in distance from one kilometre to anything longer than 10km, which is considered a marathon in swimming terms.

Age categories

Most events are split into age categories. These vary depending on the organiser. For example, many multi-discipline events follow British Triathlon age groups, while smaller swimming events might simply split you into 'open' and 'senior' classes, which is usually aged 40+. You'll usually swim together, but your time will be recorded under your age and sex class.