The Official Site of Ocean City, MD
You can also try http://www.sandhelper.com for a motorized sand wheelchair rental.
The wheelchairs on the beach are controlled by the beach patrol, but generally are removed around Labor Day. However, there are other options.
Beach wheelchairs are available at the Ocean City Police Department at 65th Street, bayside, for one or multi-days of use by advance reservation. Call 410.723.6610 for more information.
Beach wheelchairs are also available from the Ocean City Visitors Center in the Convention Center on 40th Street for one to three days of use by advance reservation. Call 410.289.2800 for more information.
Finally, PMI rentals rents these chairs, and they will deliver. You can call them at 800.320.7469 to find out more.
Be aware that these beach wheelchairs are large and do not fold up. They require a fairly large vehicle to transport (check with the people you talk to to see if it will fit in your vehicle). The chairs on the beach locations are stored at the west side of the dunes or along the boardwalk. The chairs are also not self propelled, the person in the chair will need someone to push him or her across the beach.
There is also a new business, SandHelper, that offers self-driven electric beach wheelchairs. Find out more about them here or by calling 855.743.5737. They cost $55/day to rent and have free delivery and pickup.