Del Mar's beach is wide, sandy, and uncrowded by San Diego County standards. The bluffs that rise behind it give a sense of enclosure and privacy, and the views south toward La Jolla and north toward Solana Beach are exactly what you come to coastal California for. The water is cold — this is the Pacific — but swimmable from June through September for those who want it.
Dogs are permitted on the beach north of 29th Street, which makes the northern section particularly lively. The beach is accessible by stairs down from the bluffs at several points along Coast Boulevard, and street parking is available above. In summer and during racing season the parking fills early; walk or bike if you can.