 He became commanding officer of the sixth-rate HMS "Tweed" and took part in the Battle of Luchana, an operation to defend the Port of Bilbao on the north coast of Spain, in December 1836 during the First Carlist War.As a result of this he was awarded the knight's cross of the Order of Charles III for his support for the liberal forces of Maria Christina, the Regent of Spain at the time of the minority of Isabella II, who had faced a revolt by Carlos, Count of Molina.Promoted to captain on 10 January 1837, Maitland became commanding officer of the third-rate HMS "Wellesley", flagship of Rear Admiral Frederick Maitland serving as Commander-in-Chief of the East Indies and China Station, in June 1837.