All aboard the â€˜Swim Trainâ€™ with The Big Bala Swim and The Big Welsh Swim! Two great multi-distance open water swim events in Snowdonia, North Wales, with a choice of distances from 1.3km to 9km. You will catch the narrow gauge trains down the side of the lakes with spectacular views of the mountains, and then swim back to the finish line for a truly unique experience. We have entries for junior swimmers and for non-wetsuit swimmers too! Go on, dive in!