Endeavour, under the command of skipper F. Hall, was part of a small fleet of Leigh Cockle Bawley boats that departed in convoy at 00:30 on 31 May 1940 for Dunkirk. The vessels proceeded under engine power to maintain formation under the direction of their Naval Lieutenant. During the crossing, they came under aerial attack but received protective cover from the Royal Air Force.

The Endeavour played a significant role in the evacuation, initially embarking soldiers from the beach. As the tide receded and threatened to strand the boats, she continued operations from the Mole and subsequently from the inner harbour at Dunkirk. During these rescue efforts, her rudder was damaged. Alongside the vessels Letitia and Renown, Endeavour was towed back by the coaster Ben & Lucy, which had been actively ferrying troops from the beaches throughout the previous day before cooperating closely with the cockle boats.

Unlike the ill-fated Renown, Endeavour returned safely to Ramsgate with her complement of soldiers and was commended for her valiant service.

Following the war, Endeavour was employed in fishing along the south coast of England and underwent several ownership changes. In 1986, she won two prizes in a trawler race, which included a fancy dress competition for her crew. The following year, she sank during the severe storms of 1987 while moored at Thunderbolt Pier near Chatham Historic Dockyard.

The Nautilus Diving Club, together with Thames-side sub-aqua divers, conducted a two-day salvage operation beginning at midnight, utilizing large inflatable bags to raise the vessel. This effort was undertaken voluntarily out of dedication to preserving the historic boat.

Although successfully recovered, Endeavour required extensive restoration and remained at Chatham Historic Dockyard for several years. Due to organizational changes, she was relocated to Beacon Boatyard on the Medway under the care of the Dunkirk Little Ships Restoration Trust. Subsequently, private owners acquired the vessel with the intention of restoring her to her original condition. She is currently owned by a trust committed to maintaining her in good condition and honoring her historical significance.

Fully restored, Endeavour is now based at Leigh-on-Sea in Essex and remains an active member of the Association of Dunkirk Little Ships.

Endeavour was featured in the 2015 Palau postage stamp series titled The Little Ships of Dunkirk and appeared in the 2017 film Dunkirk.