To find Mattapoiset Harbor, use NOAA Charts 13229, 13230, or 13218. The entrance to the harbor is marked by red nun No. 4, about 11 nautical miles from New Bedford, about 3.5 nautical miles from Bird Island outside Sippican Harbor, or about 8 nautical miles from the western end of Woods Hole.

Approaching from the south, round red bell No. 2 off West Island and head for the flashing green (4 sec) bell No. 9A at Nye's Ledge (course: 047 degrees magnetic). Leave Cormaorant Rock, marked by a green and white daymarker, at least 30 yards to port to play it safe (Cormorant Rock is pyramid-shaped - you may strike a rock if you pass to close to it). After you pass Cormorant Rock, you can change course for green can No. 1 off Mattapoisett Ledge, leaving it to port as you turn into the channel (course: 330 degrees magnetic), then sail or motor well away from the channel markers - they also mark underwater obstructions.

You may see local sailors passing inside cans No. 1, No. 3, or No. 5 but since there are rocks, ledges and sandbars that leave only a foot or two or three of depth, its a good idea to stay outside No. 1, turn to port and follow the well marked channel into the harbor.

From the northeast (Buzzards Bay green channel bouy No. 3), head for red nun No. 2 at Angelica Point (course: 254 degrees magnetic). Round the nun, leaving it to the starboard (course: 285 degrees magnetic) towards red nun No. 4, passing Ned's Point Light well to starboard.

From the south (Wood's Hole Green bell No. 13 at the western end of Wood's Hole Passage), head for Nye's Ledge green bell No. 9A (course: 344 degrees magentic). Leave Nye's Ledge to port, then turn 330 degrees magnetic and follow the markers into the harbor.