The captain arrived at the Melia Dunas Beach Resort and Spa in the West African island nation on 4 August and proceeded to begin drinking, the Sun reports.
At around 02:30 local time (04:30 BST) the following morning, hotel guests reportedly saw him strip off and wander into the reception, before moving onto the gym and spa, according to the newspaper.
“The pilot did not have a stitch on and reeked of alcohol,” an anonymous source inside the airline was quoted by the paper as saying.
“Anyone who saw the pilot cavorting naked in the early hours on the day before a flight would not dream of getting on a plane with him at the controls.”
He was scheduled to helm the 2,332-nautical-mile (4,318km) trip back to Gatwick on the afternoon of 6 August, but was removed from the flight.
An EasyJet spokesman said: “As soon as we were made aware, the pilot was immediately stood down from duty, in line with our procedures, pending an investigation.
“The safety of our passengers and crew is EasyJet’s highest priority.”
The airline’s code of business ethics states that staff must behave “with integrity when dealing with our people, our customers, our partners and the communities within which we operate”.