Copyright of John Saringo-Rodriguez. http://www.saringorodriguez.com/ Used with permission.
While technically not in Beppu, these two attractions can be found right on the ocean along the major road connecting Oita City and Beppu. Umitamago is the largest aquarium in Oita Prefecture, offering a 61m walk-around viewing tank and a plethora of daily marine performances by dolphins, walruses, and sea otters as their main attractions. Across the major street you’ll find Takasakiyama, a monkey reserve found at the base of Mt. Takasaki. Unlike a regular zoo, this park is notable in that none of the monkeys are kept in cages. The monkeys you can find at the park are all wild Japanese macaques who freely roam the local mountain and stop by to grab food provided by the staff and greet visitors (though mostly they’re in it for the food). Once you’re finished at either/both of these attractions, you can explore the beachside park that stretches out along Route 10 towards Oita City.
Takasaki Mountain is home to some 1500 wild Japanese macaques who roam freely on the hills of Oita. You can watch the monkeys being fed by the zoo employees and enjoy beautiful seaside views from the hills. Opposite Mt Takasaki is the Umitamago aquarium, also a popular attraction for animal lovers. Entrance to the park is 510円. See here for details.