SS Royal William was a Canadian side-wheel paddle steamship that is sometimes credited with the first crossing of the Atlantic Ocean almost entirely under steam power, in 1833, using sails only during periods of boiler maintenance.

Earlier vessels that crossed partially under steam include the British-built Dutch-owned Curaçao in 1827 and the sail-steam hybrid SS Savannah in 1819.

[2] She was designed by 21-year old James Goudie, who had served his apprenticeship, likely at Scotts Shipbuilding and Engineering Company of Greenock, Scotland,[2] a seaport on the Firth of Clyde.

[2] The ship was built in Cape Blanc, Quebec by John Saxton Campbell and George Black,[4] who laid its keel on 2 September 1830.

She departed from Pictou, Nova Scotia on 18 August 1833 with seven passengers, a small amount of freight and a large load of coal and arrived at Gravesend on the River Thames after a 25-day passage that included a stop at the Cowes, Isle of Wight for a fresh coat of paint.