From SFMTA: UPDATE: Balboa Park Station Area Improvement Project

Balboa Park Station and the surrounding area is one of the highest ridership BART stations outside of downtown San Francisco. There are multiple ongoing projects that aims to improve the safety and accessibility for road users and riders travelling to and from the area. The Green Light Rail Center Track Replacement Project, located on Geneva and San Jose avenues, is one of these projects to improve system reliability with track replacements, upgrades to the overhead contact system and installation of accessible ramps and some landscape improvements.

Beginning Saturday, May 20, the K Ingleside line will resume its normal route and service to and from Balboa Park Station.     

First stop for inbound travel will be relocated back to accessible boarding platform on San Jose Avenue. Last stop for outbound travel will be relocated to Balboa Park Station at a new platform.

The following temporary change to K-Ingleside rail service will cease on Saturday, May 20:

The first and last stop for both inbound and outbound travel is at the City College Pedestrian Bridge on Ocean Avenue
There is no direct service to the Balboa Park Station
For direct K service, passengers can transfer at Ocean and Lee to the following frequently serviced Muni routes:

8-Bayshore (transfer on the City College Terminal on Ocean and Phelan)
29-Sunset (transfer at the Ocean and Lee stop in front of Whole Foods).
49-Van Ness/Mission (transfer on the City College bus loop on Ocean and Phelan)
To reach Balboa Park Station, passengers can also walk about three accessible blocks from the City College Pedestrian Bridge stop to the Ocean Avenue entrance of the station.

Temporary Change to J-Church Rail Service will continue until construction project is complete in Fall 2017:

Both inbound and outbound service is on San Jose Avenue
For more project details, please visit http://sfmta.com/greenlightrail.