Departing Washington on 16 June, "Swatara" steamed to Norfolk, Virginia. Assigned to the European Squadron, she stood out from Hampton Roads on 27 June and called at Fayal, Azores, before arriving at Lisbon on 19 July 1866 to join flagship and other members of her squadron. After visiting Southampton, England, "Swatara" anchored at Bremerhaven, Germany, 3 August to 8 September, representing United States concern over uneasiness in Europe in the aftermath of the Austro-Prussian War. Subsequently cruising southward, "Swatara", called at Den Helder, Netherlands; Southampton, England; and the major French Atlantic seaports: Cherbourg, Brest, Lorient, Rochefort, and Bordeaux. After calling at Ferrol, Spain, "Swatara" arrived at Vigo on 26 October where the United States consul came on board to visit the ship on 6 November. Bound for Mediterranean duty, the sloop put into Tangier, Morocco; and Gibraltar; passing on to Spanish and French ports during November 1866.