Far left section of the outfield, directly behind the left fielder. Great section, don't expect to catch a home run ball. Petco Park is deep and doesn't give a whole lot of home runs throughout the season. There are 11 rows in this section. You are very close to restrooms as well as concessions. Concessions are overpriced as expected. Don't miss the beach in right field, it's really neat.
Also check out the western metal supply company building.