
While flying a routine mission for the U.S. Navy from his aircraft carrier, an emergency causes Lieutenant Robin "Rob" Crusoe (Van Dyke) to eject from his F-8 Crusader into the ocean. Crusoe drifts on the ocean in an emergency life raft for several days and nights until landing on an uninhabited island. Crusoe builds a shelter for himself, fashions new clothing out of available materials, and begins to scout the island, discovering an abandoned Japanese submarine from World War II. Scouring the submarine, Crusoe also discovers a NASA astrochimp named Floyd, played by Dinky.

Using tools and blueprints found in the submarine, Crusoe and Floyd construct a Japanese pavilion, a golf course, and a mail delivery system for sending bottles containing missives to his fiancee out to sea.

Soon after, Crusoe finds that the island is not entirely uninhabited when he encounters a beautiful island girl (Nancy Kwan), whom he names Wednesday. Wednesday recounts that due to her unwillingness to marry, her chieftain father, Tanamashuhi (Akim Tamiroff), plans to sacrifice her and her sisters to Kaboona, an immense effigy on the island with whom he pretends to communicate.

The day Tanamashu arrives on the island, Crusoe uses paraphernalia from the submarine to combat him, culminating in the destruction of the Kaboona statue.

After the battle, Crusoe and Tanamashu make peace. But when Crusoe makes it known that he does not wish to marry Wednesday, he is forced to flee to avoid her wrath. Pursued by a mob of irate island women, Crusoe is spotted by a U.S. Navy helicopter and he and Floyd narrowly escape with their lives. Large crowds turn out for their arrival on an aircraft carrier deck, but Floyd steals all the limelight.
Dick Van Dyke as LT Robin Crusoe
Nancy Kwan as Wednesday
Akim Tamiroff as Tanamashu
Arthur Malet as Umbrella Man
Tyler McVey as Captain
Peter Renaday as Pilot
Peter Duryea as Co-Pilot
John Dennis as Crew Chief
Nancy Hsueh as Native Girl
Victoria Young as Native Girl
Yvonne Ribuca as Native Girl
Bebe Louie as Native Girl
Lucia Valero as Native Girl

Lt. Robin Crusoe, U.S.N. premiered on June 29, 1966. Because the U.S. Navy cooperated by allowing the producers to film on the aircraft carrier USS Kitty Hawk, Walt Disney arranged the world premiere to be on the ship, with its crew as the only guests.
Cameraman Robert King Baggot (father of King Baggott) died of injuries received during the filming.
In 1986, the film had its first home video release on VHS. On April 12, 2005, it was released on to DVD.
The film had its theatrical release on July 29, 1966. It was paired with the live-action short Run, Appaloosa, Run! Upon its initial release, critics gave it mostly negative reviews. However, likely because of Dick Van Dyke's popularity, the film proved to be a financial hit grossing over $22 million at the box office. It was re-released to theaters in 1974.
TV Guide gave the movie 1 out of 5 stars, stating "Robinson Crusoe update is wholly contrived and not really creative."