All six people misused computers at the academy in New London and some of them participated in consensual sex acts on school grounds during the workday, academy spokesman David Santos said.
Two of the civilian workers resigned and three were disciplined. The Coast Guard discharged the service member, who was stationed at the academy and was not a cadet, Santos said.
Academy officials didn't release the names of the six people or more details of their punishments, saying personnel decisions are confidential.
"It's something that we took very seriously and the behavior of the individuals involved is certainly not indicative of the academy community," Santos told The Associated Press.
The academy didn't pursue criminal charges, he said.
Santos said the improper activities took place within the past three years and the six people were disciplined in August. The academy first released information about the allegations and punishments Tuesday to The Day of New London under a federal Freedom of Information Act request. The academy denied the newspaper's request for the 2,113-page investigation report on the wrongdoing, citing a personnel files exemption allowed for in public record laws.
Santos said not all of the computer misuse involved sexually explicit content. Coast Guard policy bans the use of government computers for inappropriate discussions. The academy also prohibits civilian workers and service members from engaging in sex acts on campus.
The academy's superintendent, Rear Adm. Sandra Stosz, said in a statement that the Coast Guard has extensive policies outlining appropriate actions and behaviors in the workplace and on government property.
"When an individual is suspected of violating these policies, we carefully follow the system in place to protect the rights of all involved in the matter," Stosz said.