Stanley Park is a gem of Vancouver. On the boarder of downtown, it is probably the most visited place in Vancouver. Walking and biking are the two most popular activities, and both can be done either around the seawall or through the forest. It is also a great place for a picnic and has some excellent beaches.
Not to be outdone (at least in the walking and biking departments) is Pacific Spirit Park, just east of UBC. At 763 hectares, it is almost twice as big a Stanley Park and has biking and hiking trails throughout. Although it doesn’t have the fame of Stanley Park, and isn’t seaside, it is still excellent for easy hiking and biking.
However, if you’re willing to make the trek (and it’s worth it), the North Shore has the best parks of all. Lynn Canyon park is foremost among the choices, with its famous suspension bridge (not to be confused with the touristy for-pay Capilano Suspension Bridge) and interesting ecology centre. Capilano River Park, home of the Cleveland dam and the Capilano Salmon Hatchery is worth a visit, as is West Vancouver’s Lighthouse Park.