SS Ionic was a steam-powered ocean liner built in 1902 by Harland and Wolff in Belfast for the White Star Line. She was the second White Star Liner to be named Ionic and served on the United Kingdom - New Zealand route. Ionic was launched at Harland and Wolff's yard at the Queen's Island in Belfast, 1902. She was originally built to carry passengers and refrigerated meat between the United Kingdom and New Zealand. Her maiden voyage from London to Wellington via Cape Town commenced 16 January 1903. Ionic was the first ship on the New Zealand route to be fitted with a Marconi wireless set.

She was built with only one buff-coloured, black topped smokestack, four passenger decks and four masts. She displayed the golden White Star Line stripe along her hull.

In 1914, at the beginning of World War I, Ionic was requisitioned as a troop ship for the New Zealand Expeditionary Force and in 1915 she narrowly missed a torpedo by less than 15 yards while steaming through the Mediterranean. On 31 January Ionic returned to her former New Zealand passenger service via the Panama Canal.

In 1934, after several refits, White Star Line and Cunard Line merged and Ionic was sold to Shaw Savill & Albion Line. She retained her name but her prefix SS was changed to RMS.

The RMS Ionic was scrapped in 1936 in Osaka, Japan. The Auckland War Memorial Museum has preserved her ships bell.