In addition to the MA options, it isn't far to drive to RI. Jamestown RI has some nice shore dives like Beavertail Point, Bull Point and Ft Wetherill. Great rocky shores with quick depth just off the beach and interesting terrain. A bonus of diving in October is that the vis is usually better in the fall as long as there are no big storms.
Also the water on the south coast of New England is warmer than it is on the north side of Cape Cod. Expect water temps in the mid to upper 50s in late October.
If you choose to stay in MA, Cape Ann (Gloucester and Rockport) diving is practically legendary. A bit chilly by comparison (I dove it last week and it was 52 at the bottom even this time of year). RI won't get that cold until November.
Also the water on the south coast of New England is warmer than it is on the north side of Cape Cod. Expect water temps in the mid to upper 50s in late October.
If you choose to stay in MA, Cape Ann (Gloucester and Rockport) diving is practically legendary. A bit chilly by comparison (I dove it last week and it was 52 at the bottom even this time of year). RI won't get that cold until November.