Umitamago (うみたまご) is an attractive aquarium just outside of Beppu. It is one of Japan's more nicely done aquariums with interesting architecture and some displays that make you feel like you are visiting a modern art museum rather than an aquarium.
Animals living in Umitamago include penguins, dolphin, seal, otter, and various fish. A visit to Umitamago Aquarium is best combined with a visit to the nearby Takasakiyama Monkey Park.
From central Beppu (Beppu Station or Beppu Kitahama bus stop), take bus number AS60 or AS61 bound for Oita Station (大分駅) and get off at Takasakiyama-Umitamago (高崎山・うみたまご). The one way ride takes ten minutes and costs 410 yen. There is approximately one bus per hour.
The "Monkey Marine Ticket" for 2450 yen consists of a round trip from Beppu or Oita Station to the monkey park in combination with admission to the aquarium and nearby Takasakiyama Monkey Park. The ticket is sold by Oita Kotsu and can be purchased at the Beppu Station tourist office or the Oita Station Bus Center.