Although the hike is only about 45 minutes to the top, plan on spending about 2-3 hours at Diamond Head State Monument, saving time for photo opps, picnics, and yoga. The park gates close at 6 pm, with the last hike offered at 4:30 pm.
Although you can't make the drive to the top of Diamond Head, you can drive around it. A typical hike up to the top is only about 45 minutes, offering unparalleled views of Honolulu and the Pacific Ocean.