Oahu Island has several campgrounds managed by Hawaii State and Honolulu County.
State Park Permits - Reservations should be made 30 days in advance. Camping fees for Hawaii State Parks are $5.00 per campsite per night, with the exception of Na Pali Coast State Park, Kaua'i. The fee for camping in Na Pali Coast State Park, which has camping areas at Hanakapi'ai, Hanakoa, Kalalau and Miloli'i, is $10.00 per person per night.Lodging fees for Hawaii State Parks range from $20.00 per night for screened A-Frame shelters to $55.00 per night for a group cabin. For the fee schedule see: Permits and Fees.
State Parks on the Island of O'ahu - State parks are open year-round.
Malaekahana Camp Grounds - From ancient times, Malaekahana has been known as a magical place, serving as a "Puuhonua" (Place of Refuge). Today, as the first native-run Hawaiian State Park area, it is still a haven (and one of the safest campgrounds in Hawaii). No pool, no TV, no phone - only the sound of the surf to distract you.
Oahu Camping - Gereral info as well as map with both County and State campsites.