RNZ reports the Micronesian country has five athletes competing in Rio in weightlifting, swimming and athletics.
Twenty-three year old swimmer Giordan Harris is the veteran of the group, having competed at the London Games four years ago.
The other four are all between 17 and 19 years-old.
The Secretary General of the Marshall Islands National Olympic Committee, Terry Sasser, said they are building a group of athletes who would reach their peak over the next decade.
"We've learned the Olympic solidarity scheme. It's thousands of hours and years of practice before you can get to an elite level so I think our President Ken Kramer has pretty much put in a mandate that wait, let's look at long term, let's look at eight years ahead - not two years, not four years (but) eight years...so we're basically bringing a junior team to the Olympic Games."
Terry Sasser's daughter, Mattie Sasser, was the Marshall Islands first athlete to compete in Rio, finishing in 11th place in the women's 58kg weightlifting division.
Giordan Harris finished 63rd in the men's 50m freestyle heats.
Photo: Marshall Islands National Olympic Committee/Facebook - Mathlynn “Mattie” Sasser, wieghtlifter