Sasebo Naval District
Upon commissioning, "I-63" was assigned to Submarine Division 28, in which she spent her entire career. The division was assigned to the Sasebo Naval District on 24 December 1929, then was reassigned to Submarine Squadron 2 in the 2nd Fleet in the Combined Fleet on 1 December 1930, to Submarine Squadron 1 in the 1st Fleet in the Combined Fleet on 1 December 1932, and to the Sasebo Defense Division in the Sasebo Naval District on 15 November 1933. On 20 March 1934, "I-63" was decommissioned and placed in reserve, and while she was in reserve Submarine Division 28 was reassigned to the Sasebo Guard Squadron on 15 November 1934.