Liz Fraser was originally cast as Sally but accidentally talked herself out of the role during an ill-advised conversation with distributor boss Stuart Levy.

Carry On Jack was writer Talbot Rothwell's first original Carry On film, and also the series' first historical romp. Inspired by the 1962 film HMS Defiant, original sets, ships and props from the earlier title were reused.

Like Cabby before it, the film was not originally intended to be a Carry On, and produced under the title Up The Armada.