Based on the Coast Guard Historian’s timeline, https://www.history.uscg.mil/research/chronology/
With inspiration from Mike Kelso

June 30

1932  The Steamboat Inspection Service and Bureau of Navigation were combined to form the Bureau of Navigation and Steamboat Inspection (47 Stat. L., 415).  The new agency remained under the control of the Commerce Department.

1933  The airways division, which had been conducted as a division of the Lighthouse Service, but under the administrative supervision of the Assistant Secretary for Aeronautics, Department of Commerce, was separated from the Lighthouse Service. (USLHS AR 1933, p. 97).

1933  The Coast Guard reported that during its existence, from January 28, 1915 through the end of the Fiscal Year (June 30) of 1933 the service had either  “rescued from peril” or “saved” the lives of 60,982 persons and the value of vessels and cargoes the Coast Guard saved or assisted was $659,632,287 (CGM, April, 1934, p. 28).

1939  “The total personnel of the Service as of June 30, 1939, was 5,355, consisting of 4,119 full-time and 1,156 part-time employees, the former including 1, 170 light keepers and assistants; 56 light attendants; 1,995 officers and crews of lightships and tenders; 113 Bureau officers, engineers and draftsmen, and district superintendents and technical assistants; 226 clerks, messengers, janitors, and office laborers; 157 depot keepers and assistants, including watchmen and laborers; and 482 field-force employees engaged in construction and repair work.”

1939  “At the end of the year, the total number of lighthouse tenders was 65, of which 64 were in commission and 1 was out of commission and advertised for sale.  Of the vessels in commission, 42 were steam-propelled, 18 had diesel engines, and 4 had diesel-electric drive.  The average age of the fleet of tenders is 19.52 years.  There are 10 tenders, aggregating 8,535 tons, 35 years of age and over. Thirty lighthouse tenders are equipped with radiotelegraph; 38 with radio direction finders; and 55 with radiotelephones.”

1939  “Lightships were maintained on 30 stations during the year.  At the close of the year, the total number of lightships was 43, which included 9 relief ships and 4 ships out of commission.”

1939  “The total number of aids to navigation maintained by the Lighthouse Service at the close of the fiscal year was 29,606, a net increase of 849 over the previous year.”

Coast Guardsmen and war horses stand shoreside inspection. USCG Historian’s Office

1942  The Coast Guard’s Beach Patrol Division was established at Coast Guard Headquarters under the command of Captain Raymond J. Mauerman, USCG.

1946  The general World War II demobilization task was completed with all Separation Centers decommissioned, resulting in a reduced number of Coast Guard personnel to 23,000 officers and enlisted personnel from a wartime peak of about 171,000 on June 30, 1945.

1946  By this date, all lightships removed from their stations as a war measure had been restored, except Fire Island Lightship which had been replaced by a large-type whistle buoy offshore and a radio-beacon on shore at Fire Island Light Station, New York.

1946  The U .S. Navy returned the Coast Guard’s eleven air stations to the operational control of the Coast Guard.

1947  The Fourth Coast Guard District, which comprised parts of New Jersey, Pennsylvania, and Delaware and was based out of Philadelphia, was abolished and the functions, responsibilities, and facilities in this area were transferred to the Third Coast Guard District, based at New York, New York.  Additionally the Seventeenth Coast Guard District was abolished, and the Territory of Alaska, which it comprised, was added to the Thirteenth Coast Guard District, which included Washington, Oregon, Idaho, Montana, and Wyoming.

1987  As part of a major reorganization and consolidation effort the Coast Guard disestablished the Third and Twelfth Coast Guard districts.