By car
Parking at most attractions is convenient, though on-street parking in downtown areas is sometimes at a premium. If you are driving to downtown on the weekend, parking is free in the garage at the World Exchange Plaza. There are entrances to the garage on both Metcalfe Street and Queen Street. A map is useful if you are going to be driving around downtown as many of the streets are one-way and more than one visitor has complained about navigating the downtown core.
Most major car rental companies have several offices in Ottawa with all of them represented downtown and at the airport.
By bike
There are usually a few options for renting bicycles downtown (http://bikedump.com/), and of course you can always bring your own. Ottawa is very accessible to cyclists. Again, you may want to start immediately opposite Parliament Hill to pick up a map of the area or find a bicycle rental. Cycling to the attractions around downtown Ottawa is a great way to get around, but don't ignore the Gatineau side of the river. They have several attractions along the river including the Museum of Civilization and if you want to really stretch your legs, Gatineau Park has many great cycling paths.
The city is criss-crossed by over 170km of bicycle paths, some of which are shared with motorists, and some are shared with pedestrians. The city provides Interactive Pathways and Other Maps (http://canadascapital.ca/...). In addition, the city closes 50 km of roadways to cars every Sunday during the summer from Victoria Day to Labour Day allowing for cycling, in-line skating and walking on these roadways.
OC Transpo has bicycle racks on the front of many buses. You can load your bike on the rack and then ride the bus for the normal passenger fare. The O-Train will take bikes as well.
By taxi
Taxis are easy to find downtown; elsewhere, phone for a cab. All taxis should have a meter and the base charge is $2.45. A ride from downtown to the airport will be costly, running between $25 and C$35. Cabs will not take credit cards for fares below $10. Most cab drivers know Ottawa well, but have clear instructions if you're going anywhere in the suburbs as many developments in the outskirts are relatively new. Ottawa cabs aren't supposed to pick up customers off the street on the Quebec side; the converse applies to Quebec cabs in Ottawa. You may phone a Quebec cab if you are in Ottawa and vice versa.
On foot
Ottawa is a great city to explore on foot. With pedestrian-friendly streets and the density of attractions, a car is expensive and unnecessary for the most part. An excellent place to start any tour of Ottawa is the Capital Information Kiosk, located at 111 Albert Street in the World Exchange Plaza. They have maps and brochures for most tourist attractions in Ottawa, many of which are within walking distance.
Popular pedestrian areas, especially during spring and summer months, are the various streets in the ByWard Market. Sparks Street, running through downtown parallel to the Parliament Buildings, is a popular pedestrian area during the day and night, particularly in the spring and summer months.
Guided walking tours are available with Ottawa Walking Tours (http://ottawawalkingtours...) others such as Around About Ottawa (http://aroundaboutottawa.com). There is so much to see and do in the Nation's Capital that a tour guide will maximize a visitor's time and experience in this beautiful city. All tours include some history as well as other tidbits of trivia not commonly known. Especially popular is the Haunted Walk of Ottawa (http://hauntedwalk.com) that provides a variety of walking tours focusing on the city's darker and more offbeat past.
Remember, Ottawa is a city with a truly continental climate. In winter, exposed skin can freeze in minutes or less, so layer up on the clothing and protect yourself by wearing a hat toque or hunters cap, gloves and boots. Despite being closer to the North Pole than the equator, summer temperature and humidity can be oppressively high, so bring water if you're doing any amount of walking or cycling. If you are on the public pathways near the canal or the river, there are drinking fountains to refill your bottles. Also, don't forget the mosquito repellent.
Public Transit
The city's public transit is run by OC Transpo (http://octranspo.com/) and includes the bus service as well as the O-Train light rail system. The network includes the Transitway, a bus rapid transit system running through and out of downtown, with frequent service on the order of 1 to 2 minutes, depending on your stop and final destination, at rush hour.
The bus fare for regular routes is $3.30 or two tickets. Tickets cost $1.30 each and are available from local stores in sheets of six but some stores will sell smaller numbers at a time. Children 6 to 11 years of age require only one ticket. Upon boarding, make sure that you are given a transfer, which allows you to ride any number of buses or trains until its expiry in roughly 1.5 hours. The transfer is also your proof of payment in case fare enforcers board the bus to check that passengers have paid. A day pass can be purchased on any bus for $7.75 and is good for both buses and the train. On Sundays, families up to two adults and four children, age 11 and under can share a day pass.
The O-Train operates on a "Proof of Payment" POP system. Valid proof of payment is a bus transfer see above, or an O-Train ticket purchased from the automated vending machines for $2.75. Note that the vending machine does not accept bus tickets, nor are bus tickets acceptable proof of payment. Children 11 and under can ride the O-Train for free. Articulated buses the long ones use this same POP system as well, where rear boarding is available to pass holders.
Although the downtown is very walkable, if you are within the downtown area Lebreton station to Campus station, you can take any bus going east-west. If you are going to the ByWard Market from the Transitway #95, #96, #97, #85, #86, #87, get off at Rideau Centre and walk through the mall to the other end. To go North-South, take the #4 to Catherine Street, edge of Centretown, the #7 edge of Old Ottawa South or the #1 all the way down Bank Street to Ottawa South.
The Ottawa Transitway dedicated roads on which only buses are allowed offers speedy travel to outlying areas, where you can then transfer over to local buses, if walking is not an option.