Old Harbor is a man-made yacht basin located on the east side of Block Island, almost geographically opposite from Great Salt Pond, which is on the west side of the island. Old Harbor is the primary landing point for the mainland ferries that run on regular schedules to the island, but there is also a marina with space here and limited mooring facilities, too. Anchoring is prohibited due to the ferry traffic that comes and goes at all hours.
Inside of the Old Harbor breakwaters is a singe marina on the far side of the small harbor that has facilities and slips available to transient guests. Moorings are available to starboard on entry, and there are several points for landing your dinghy around the harbors edge (be sure to lock and chain your dinghy here).
From the east side of Block Island, set a course for flashing green 3 at the east breakwater to Old Harbor. Once you have sighted this light, you will see green can 5, and then red nun 6 before flashing red light 8 marks the west breakwater to the harbor (shorter than the east breakwater).
The harbor inlet and the harbor itself have depths of 10 to 15 feet, and once you have negotiated the breakwalls, you will see the Old Harbor Marina to port and a small mooring field to starboard. Many people simply beach their dinghies on the sandy beach areas to go ashore.