We strongly recommend the hike from Cardiff State Beach to South Carlsbad State Beach. We took two cars, dropped one off at the destination point and drove South to the starting point. The entire hike, one way, is 5.5 miles. It took us two hours and twenty minutes. We begun our hike at 7:20AM, so most of the time we were in the shade provided by the cliffs running along the beach facing West. We intentionally timed our hike during low tide as there are two areas that are inaccessible during high tide.
Cardiff State Beach GPS coordinates:
North 33° 1.026', West 117° 16.890'
South Carlsbad State Beach [South Ponto]:
North 33° 5.114', West 117° 18.698'
