The House flag of Irish Shipping Ltd, Dublin. A white rectangular flag with a red St Patrick's saltire. The arms of the four Irish provinces Leinster, Connacht, Ulster and Munster, are placed in the quarters. The flag is made of a wool and synthetic fibre bunting. It has a cotton hoist and is machine sewn. The four shields are printed on cotton appliqués. A rope and toggle is attached.

The company was formed 21st March 1941 as an Irish national shipping company to acquire, operate and maintain a deep-sea merchant fleet to supply the neutral Irish Republic during the war. After the war the company took over management and operation of its own vessels. Its tonnage was initially time-chartered pending the delivery of its own newly ordered vessels. By 1959 Irish Shipping Ltd had 20 ships - traditional steamers, motor ships, colliers and small bulk carriers.

In 1964 Irish Shipping took a 40% holding in Palgrave Murphy & Co. Ltd and in 1967 began a joint North Atlantic service with Manchester Liners Ltd. In 1968, a continental ferry link began with a weekly roll-on-roll-off ferry service between Rosslare and Le Havre, run by a consortium comprising Irish Shipping Ltd, the French company Soc. Anon de Gerance et d’Armement and the British General Steam Navigation Co. Ltd. This service closed in 1971 due to withdrawal of the other partners. A joint venture – Celtic Bulk Carriers – commenced with Reardon Smith Ltd when four new bulk carriers entered service in 1973.

The Irish Continental Line was formed in 1973 to operate a ferry between Rosslare and Le Havre/Cherbourg, jointly owned by Irish Shipping, Fearnley & Eger and Lion Ferry A/B. The company entered ship management in 1976 and went into liquidation in November 1984. Initially, the House flag had the company initials in the quarters, but these were replaced with the arms of the four provinces in 1947.