From 2004 to 2021 we monitored the Western Snowy Plover (Charadrius nivosus nivosus) in coastal Los Angeles and Orange counties, California. Following an absence of 68 years, it returned to nest in 2017. Since then, the plovers have nested at three locations in Los Angeles County and four in Orange County, where numbers of nests at Anaheim Bay, Bolsa Chica State Beach, and Huntington State Beach increased. Protective beach management and nest enclosures presumably contributed to the increase of nests and hatching success at these sites. However, the number of nonbreeding Snowy Plovers in coastal Los Angeles County has declined, most steeply at Zuma Beach. At nonbreeding roosts in Orange County numbers at Balboa Beach and San Onofre State Beach declined, but countywide numbers were stable. All sites at which plovers roost experience human-related disturbance, which may include vehicles driving through them regularly, beach grooming that removes wrack and foraging resources, dogs chasing and flushing roosting plovers, and nearby large recreational events and summer camps as nonbreeding plovers return in July. Most sites lack consistent protective measures. Plover mortality has resulted from vehicle strikes and dogs. We recommend management that includes the establishment of special protection zones, restrictions on sand grooming, wrack removal, and vehicle traffic, and installation of protective enclosures around roost sites.