Aerial view of Mission Bay near San Diego, California, looking east. Mission Bay is a bay located south of the Pacific Beach community of San Diego, California. The bay is part of the recreational Mission Bay Park, which is the largest man-made aquatic park in the country, consisting of 4,235 acres, approximately 46% land and 54% water. The combined area makes Mission Bay Park the ninth largest municipally-owned park in the United States. Wakeboarding, jet skiing, sailing, and camping are popular on the bay (wiki 2009).