The simplest way from downtown Vancouver to Pacific Spirit Regional Park is a bus toward UBC, then a short walk to a trailhead. The park sits on the west side of the city and has many entrances, so the best stop depends on which trail you want.
Buses along Broadway and West 4th
Several bus routes pass the park. The ones listed for reaching its entrances are the 4, 14, 25, 33, 41, 49, 84 and 99. The 99 B-Line is the express service along Broadway toward UBC, and local routes then serve the trailheads. Which one suits you depends on the entrance, so open the TransLink trip planner, enter your downtown starting point and the park or a specific entrance, and read off the current options.
Travel times and frequencies change by time of day and on weekends. The planner shows live departures, which beats trusting any printed number.
Driving in from the west side
By car you reach the park by heading west on Southwest Marine Drive, 16th Avenue, 10th Avenue, 4th Avenue or Northwest Marine Drive. West 16th Avenue is often suggested as the easiest entry for a first visit. Chancellor Boulevard to the north and Marine Drive to the south near the coast are other places to park.
There are several lots spread around the park, and some areas also have street parking. The park map shows where each lot is, which is worth a look before you leave. Check posted signs at whichever lot you choose for rules and limits.
A taxi to the trailhead you want
The park is large, and a taxi or rideshare can drop you right at the entrance you picked instead of at a bus stop a walk away. Tell the driver the entrance or the nearest street, since the park has no single front door. The Vancouver taxi page covers local service, and the taxi fare estimator gives a rough fare before you book.
Cell signal can drop in the wooded parts, so save an offline map and decide where you will meet your ride back. Wear shoes that handle mud, because trails stay damp long after rain.