In March 1935, he was appointed honorary sub-lieutenant[3] and passed naval exams in gunnery and navigation, which would have entitled him to a lieutenant’s commission in the Royal Navy if he gave up his Spanish nationality.

He met his future wife at a party hosted by Victor Emmanuel III of Italy on the day before his sister (Infanta Beatriz) was to be married.

Just before the birth of the Infante Juan Carlos, the Count of Barcelona decided to go hunting, with the doctor telling him and his wife that the future king would not be born for weeks.

[4] In 1931, Juan was subject to dynastic negotiations between the Alfonsists and the Carlists, concluded in so-called Pact of Territet, which was never implemented.

In 1936, his father sent him to participate in the Spanish Civil War but he was arrested near the French border, and sent back by General Emilio Mola.

On 19 March 1945, he announced a manifesto in Lausanne, demanding he replace Francisco Franco: Today, six years after the Civil War, the regime established by General Franco, inspired from the start by the totalitarian systems and the Axis powers, so contrary to the character and tradition of our people, is fundamentally incompatible with the circumstances, which the present war is creating in the world.

However, Franco was afraid that Juan would roll back the Spanish State because he favoured constitutional monarchy, which would restore parliamentary democracy.

He was fond of the sea, and joined the Naval School at San Fernando, Cádiz, and had tattoos of a marine theme from his time in the British Royal Navy.