The route

750m Distance

A very achievable swim and the ideal choice for first-timers. This short lake route is designed to build confidence and ease you into open water swimming. Equivalent to 30 lengths of a 25m pool.

Cut-off time: 40 minutes

2.0km Distance

A more challenging swim, perfect for those with some open water experience. This longer lake loop gives you time to settle into your rhythm and enjoy the fresh water setting.

Cut-off time: 1 hour 30 minutes

3.9km Distance

Set yourself a real challenge with the full Ironman swim distance. This longer lake route is designed for confident and experienced open water swimmers looking to test their stamina.

Cut-off times: reach 1.9km in 45 minutes and finish in 1 hour 45 minutes.

We recommend wearing a wetsuit for this distance.

Safety & entry requirements

The water temperature at this time of year is usually around 12°C. Fresh water is also less buoyant than the sea, which can make the swim feel more challenging. You’ll need some open water swimming experience to take part, and should only enter a distance you’ve previously swum in similar conditions.

Tow-floats are compulsory for all swimmers. You can bring your own, hire one with your entry, or rent on the day at the information desk.

Our safety team of kayakers and rescue boats will be on the water throughout, with a medical team on hand for your support.

Part of the Great Swim Trilogy

This is the second event in the Gaelforce Great Swim Trilogy. Swim the River Shannon, Lough Derg, and Killary Fjord to complete the trilogy and earn an exclusive Gaelforce Great Swim Trilogy mystery gift.

Sign up for all three events before 16 May 2026 to qualify.

The Trilogy is designed as a journey - from lake, to river, to sea. With events in late spring, mid-summer, and autumn, you can build your experience and distance step by step, creating the perfect swimming challenge for the year.

Are you up for the challenge?

Gaelforce Great River Swim | Gaelforce Great Fjord Swim

Route map