Portland Walking Tours (503/774-4522, www.portlandwalkingtours.com ) offers a variety of tours related to art, architecture, history, and food of the downtown area. Most depart from the visitors center at Pioneer Courthouse Square .
The 2.5-hour “Best of Portland” tour visits public art, downtown parks, and the waterfront ($19 adults); for the same price the “Underground Portland” tour captures the spirit of the city’s historic Old Town  and Chinatown , culminating in a visit to an underground business district and a Shanghai tunnel.
Get out on the Willamette to see the river side of Portland . The Portland Spirit (503/224-3900 or 800/224-3901, www.portlandspirit.com ) offers a variety of sightseeing and dining cruises aboard a 150-foot yacht with three public decks. The usual tour route is between downtown  and Lake Oswego, south (upstream) from Portland.
Two-hour lunch cruises ($38 adults) and 2.5-hour dinner cruises ($68 adults) are available Monday–Saturday, and there are also two-hour brunch cruises ($48) Saturday–Sunday. Sightseeing passengers may also accompany any dining cruise ($28 adults for lunch and brunch sailings, $38 for dinner sailings) with drinks and snacks available on board.
Most cruises depart from the dock at Salmon Street Springs Fountain (at the base of SW Salmon St. at Waterfront Park ). Call or check the website for departure times and to learn about other cruise options.
Willamette Jetboat Excursions (503/231-1532 or 888/538-2628, www.willamettejet.com ) offers two jet-boat tours of the Willamette River. A two-hour cruise available daily May–September travels up to Willamette Falls at Oregon City  ($35 adults, $23 children ages 4–11) while a one-hour Bridges and Harbor Tour (late June–Sept. 1, $25 adults, $18 children ages 4–11) explores the waterfront and all 10 of downtown Portland ’s bridges. Tours depart from the OMSI  dock (1945 SE Water Ave.).
Ecotours of Oregon (3127 SE 23rd Ave., Portland 97202, 503/245-1428 or 888/868-7733, www.ecotours-of-oregon.com ) runs tours blending ecological understanding with good times. Door-to-door van transport from anywhere in the Portland  area, lunch, and commentary are included in itineraries such as Portland microbrewery tours ($45) and whale-watching ($78). Packages focusing on winery tours, Mount St. Helens , and the Columbia Gorge  typify the focus of this small company. Trips are usually confined to vans of six with a professional naturalist-historian guide.