You could also take the 42 Waikiki Beach and Hotels bus on Ala Moana Boulevard fronting Ala Moana Park, but service is limited in the evenings.
Buses run frequently.
Travel time is approximately 15-20 minutes. After reaching Sea Life Park, stay on the bus and continue to the entrance of Bellows Beach on Kalanianaole Hwy. To return, board 57 Kailua-Sea Life Park on Kalanianaole Hwy. After reaching Sea Life Park, stay on the bus and continue to Waikiki. Buses run 30 minutes to an hour apart.