With 400 miles of coastal waters Rhode Island has constructed a number of lighthouses over the centuries. Although you can see a few of these from land the best way to see them is by boat. Save the Bay Foundation
is sponsoring very special tours which include viewing 20 lighthouses from the water and actually touring the Rose Island Light.
Currently two dates have openings for this exceptional full day outing: June 15 and Sept. 28. (Coincidentally Blueberry Cove Inn has openings for both dates.)
Visit Save the Bay for more information: http://www.savebay.org/lighthouse
If you can't make those dates or spend an entire day on the water you might want to check out Rhode Island Bay Cruises
which offers 90 minute cruises to view 10 lighthouses. Try to make your reservations in advance though as these are extremely popular.