Donated to the University of California in 1952 by Lena Kendall and the A. H. Frost estate, the Kendall-Frost Mission Bay Marsh Reserve protects 20 acres of coastal salt marsh at 2055 Pacific Beach Dr in the 92109 zip code. Administered by UC San Diego as part of the University of California Natural Reserve System, the site preserves one of the last remaining tidal wetlands in Mission Bay, a landscape that once extended across the entire estuary before mid-century dredging reshaped the shoreline. Habitats within the reserve range from high marsh and salt flats to tidal channels and submerged shoreline, supporting plant communities of California cordgrass, perennial pickleweed, and sea lavender. At least two endangered bird species depend on the marsh: Ridgway's rail and Belding's savannah sparrow, both monitored through artificial nesting platforms installed in 1987 to protect eggs from high tides and predators. The city of San Diego's adjacent Northern Wildlife Preserve expands the protected habitat to roughly 40 acres, adding mudflats, a sand spit, and eelgrass beds where Pacific Beach Surf School students and other bay users can often spot great blue herons and long-billed curlews from the water. In 2024, UC San Diego opened a new Field Station and Community Learning Center at the marsh, raising over $1.7 million with support from the School of Biological Sciences, the San Diego Audubon Society, and City Council President Pro Tem Joe LaCava. Over 40 doctoral dissertations and more than 100 published research papers have originated from studies conducted at the site. The reserve's annual Love Your Wetlands Day, held the first Saturday of February, draws hundreds of visitors for native plant restoration, trash collection, and guided tours. A Honda-funded grant supports ongoing collaboration between the San Diego Audubon Society, Scripps Institution of Oceanography, and Kumeyaay Nation leaders to integrate Indigenous perspectives into marsh management. Morning visitors heading out from the reserve can find breakfast at Broken Yolk Cafe on Mission Boulevard. The reserve is open 24 hours and free to the public, with an observation deck and free street parking along Pacific Beach Drive.