-- "Boston by Sea: A Living History in Story, Sites & Song," a 90-minute multimedia tour developed by the Boston History Collaborative, departs Sat. and Sun. at 10:30 a.m. and 1 p.m. The cruise includes live theater performances, sea chanteys, and videos. Fare $19, $17 for seniors, $10 for children under 12.

-- Constitution cruises, which are narrated and offer the chance to board the USS Constitution, depart from Long Wharf every hour on the half-hour from 10:30 a.m. to 4:30 p.m., and leave the Charlestown Navy Yard hourly from 11 a.m. to 5 p.m. The trip lasts about 45 minutes. Fare $10, $9 for seniors and students, $8 for children under 12.

-- George's Island ferry departs daily from Long Wharf at 10 a.m., noon, 2 p.m., and 4 p.m. and weekends from Hingham (Hewitt's Cove) at 10 a.m., 12:15 p.m., 2:15 p.m. and 4 p.m. Fare $8, $7 for seniors, $6 for children under 12. From George's Island, you can take a free water taxi to other Boston Harbor islands.

-- Historic Sightseeing Cruise departs Mon. through Fri. at 11 a.m. and 1 p.m., and also on Sat. and Sun. at 11 a.m. The trip lasts about 90 minutes. Fare $17, $14 for seniors and students, $12 for children under 12.

-- Sunset cruises, leaving daily at 7 p.m., include the Constitution's "sunset cannon serenade." The trip lasts about 90 minutes. Fare $17, $14 for seniors, $12 for children under 12.

http://www.bostonharborcruises.com.