Farthest distance cycling underwater

The farthest distance cycled underwater is 3.04 km (1.87 miles) achieved by Ashrita Furman (USA) at Complexo Olímpico de Piscinas de Coimbra in Coimbra, Portugal on 22 September 2011.

Ashrita took 3 hours 35 minutes and 23 seconds to complete his attempt.
He completed 66 laps of a 46 m course