Riley asked his fellow governors to join him in urging the boycott of Aruba, where 18-year-old Natalee Holloway was last seen on May 30.
Her mother, Beth Holloway-Twitty, joined Riley at the Alabama Capitol for the boycott announcement. She contends Aruban authorities have failed to adequately investigate the possible murder of her daughter, who was with aand two on the night she disappeared.
The young men were held for a time but have been released.
Aruban officials did not immediately respond Tuesday to requests for comment by The Associated Press.