The 19-year-old has failed to break into the first team at Ajax - but did captain Jong Ajax in the Eerste Divisie where his side finished 14th last term.
He will move to Excelsior for the coming campaign after Marinus Dijkhuizen's men secured promotion to the top flight courtesy of victory against RKC Waalwijk in the play-offs.
Kuipers will remain on loan with his new club until the end of June next year before his contract expires at Ajax.
"Bas can become a very good footballer, he has great control on the ball and is fond of attacking," Dijkhuizen told Excelsior's official website.
"I love ball-playing full-backs who can get forward. This is a good step for him and it's great for us that we have the left-back we were looking for.''
Kuipers could make his Excelsior debut against NAC Breda on Saturday in the opening week of the Eredivisie.
