HONG KONG—Hong Kong's Disney theme park said it is investing US$550 million on a third hotel, after record attendance helped deliver the park's biggest annual profit since it opened in 2005.

Hong Kong Disneyland's new hotel, with an "exotic locations" theme, will increase the number of hotel rooms at the resort by 75% when it opens in 2017. The park is the smallest of Disney's global resorts.

The...