An adaptation of standard governmental forms to tropical Hawaii, the three-story, reinforced-concrete post office successfully integrates a formal classical composition with an open informality. A two-story colonnade of Tuscan columns is tempered by the green tile hipped roof with overhanging eaves, and the open lobby. Service counters, tables, and post-boxes are situated on a central lanai, allowing customers to conduct business outdoors. Two wings added in 1938 adhere closely to the original design and finishes, and further enhance the convivial indoor-outdoor relationship through their use of lanai as corridors. The building bears a high level of detailing, from its marble and terrazzo floors to its spiral stair with marble treads and wrought-iron banister, whose newel post is capped by a pineapple finial. The third-floor courtroom unfortunately has been remodeled into office space.