From September 1939 until September 1942, the HX series carried traffic from Halifax, Nova Scotia, to Liverpool. Subsequent to September 1942, and until the end of the war, this series departed from New York. Slower vessels were routed in the SC series while faster vessels sailed in the short lived HXF series. Additionally, the BHX series sailed from Bermuda and rendezvoused with the HX convoy of the same number.

There were no cancelled convoys.