In May 1940, the acting director of the Division of Plans and Policies, U.S. Marine Corps, issued a memo asking for ideas about the employment of parachute troops. The training of groups of Marines to become paratroopers began in October 1940, and continued at a snail's pace; the 1st Parachute Battalion took nearly a year and a half to constitute its three companies, and was only at 60 percent of its TO&E strength by March 1942. The 2nd Parachute Battalion was formed (as the 2nd Parachute Company, later redesigned Company A, 2nd Parachute Battalion) on March 22, 1941, and the 3rd Battalion on September 16, 1942; the 3rd Battalion reached full strength far quicker than the other two due to improved training, being fully constituted within four months, by the end of December 1942. The three battalions were eventually organized into the 1st Marine Parachute Regiment. The "Paramarines" never actually dropped into combat, (as the Marine Corps lacked the number of transport aircraft needed to do so) but fought as ground troops in operations conducted in 1942 and 1943 at Gavutu, (August 1942) Tanambogo, (Augustt 1942) Guadalcanal, (September 1942) Choiseul, (October 1943) and Bougainville (November 1943) Four parachute operations were planned, but never executed;
Capturing Villa airfield on Kolombangara Island, planned for July 1943; the island was cut off via naval means and the Japanese evacuated it in September and October 1943
Capturing Kahili and Kara airfields on Bougainville, planned for September 1943
Capturing the town of Kavieng on the island of New Britain, planned for April 1944
Capturing the Japanese seaplane base at Rekata Bay, Santa Isabel island; (in the Solomon Islands) the island was cut off and the Japanese evacuated the base in September 1943
It was eventually decided that Marine special units were not worth the upkeep cost; the Paramarines were disbanded on December 30, 1943, and the other Marine special operations unit, the Marine Raiders, also ceased to exist on February 29, 1944.
Sources:
U.S. Airborne Units in the Pacific Theater 1942–45, by Gordon L. Rottman
Silk Chutes and Hard Fighting: U.S. Marine Corps Parachute Units in WWII, by Lieutenant Colonel Jon. T. Hoffman, U.S. Marine Corps Reserve