Fastest aggregate time to swim the GB Three Lakes Challenge (female)

The fastest aggregate time to swim the Three Lakes Challenge (female) in Great Britain is 16 hours 30 minutes 31 seconds, achieved by Helen Hislop (UK), between 1 and 2 September 2025, as ratified by the British Long Distance Swimming Association.

The Three Lakes Challenge comprises the three longest lakes in each nation of mainland UK: Loch Awe in Scotland, Lake Windermere in England and Llyn Tegid (Bala Lake) in Wales. The total distance to cover across the three lakes is approximately 60 km (37.3 mi).

Wearing only a swimsuit, cap and goggles (as per traditional marathon swimming standards), Hislop started the triple-swim challenge in Loch Awe on 1 September 2025 at 6.45 a.m., departing from Torran Bay and ending at Kilchurn Castle, Dalmally (swim time: 9 hr 58 min 25 sec). Next was Windermere, setting out at 11.21 p.m. from Fell Foot and finishing in Waterhead (5 hr 2 min 26 sec). Finally, Hislop traversed Llyn Tegid in Wales, departing from the Glanllyn Caravan & Camping Park at 9 a.m. and arriving at Bala Adventure and Watersports Centre at 10.29 a.m. (1 hr 29 min 40 sec).

When factoring in travel time between the lakes as well, the full duration of the attempt was 27 hr 44 min.