From Akita Airport, you can either rent a car and drive to GAO via Akita Expressway, or take a limousine bus to Akita Sta., ride JR Oga Line to Hadachi Sta., and then take a local bus to GAO (Oga-Kita route).
Bus Fare Ā@ Ā@Ā@ Limousine Bus (Airport - Akita Sta.) 890 Yen (one way per adult)
Hadachi Sta. - Oga Aquarium GAO 860 Yen (one way per adult)