Cardiff, is a beach community located between Encinitas and Solana Beach. The Pacific Ocean is to the west of Cardiff, Encinitas on its east and north, and beach and lagoon on its south. With a population of under 12,000, Cardiff-by-the-Sea operates as part of the city of Encinitas, but has its own ZIP code 92007.

In 1911, this former farming community began to develop when developer J. Frank Cullen broke ground to build new homes. It is reported by the Cardiff Chamber of Commerce that it was Frank Cullen's wife, a native of Cardiff, Wales, who persuaded him to name the community, "Cardiff". Many streets in Cardiff bear names this English-born landowner grew up with in his native UK. The names of, "Birmingham", "Oxford", "Chesterfield" and "Manchester" are major streets in this city.

Cardiff Reef ("The Reef") is a popular surf spot in Cardiff that produces waves both professional and novice surfers enjoy year round. Surfing at The Reef has progressed from just a few surfers in the '50s to become one of the most popular surfing spots in San Diego County. Cardiff Reef and nearby surf spot, Pipes, are famous for their smooth and consistent wave shape. When the tide is low, a beautiful flat rock reef is revealed that extends 50 yards from shore. Exploring these tide pools is a popular activity for visitors of Cardiff.