Answer
Water, sunscreen, insect repellent, snacks, and cash/card for entry are essentials. Binoculars enhance horse and bird watching. Leave drones and fireworks behind unless explicitly permitted—assume they are restricted.
Sources: National Park Service — Assateague
Editorial visitor guidance for Ocean City, Maryland. Confirm current Town of Ocean City, Maryland DNR, NPS Assateague, and NWS rules when regulations or safety apply.
