The Cardiff/Encinitas Coastal Rail Trail (part of the longer, ongoing project to eventually run 44 miles between Oceanside and San Diego) is a beautiful, mellow, and well-maintained pathway that runs from the corner of Chesterfield Dr. & San Elijo Ave. (right across the street from the Patagonia store in Cardiff) to the corner of Santa Fe Dr. and San Elijo Ave.
This particular stretch of the Coastal Rail Trail is about 1.3 miles long, and is the perfect length for a morning jog back and forth, a dog walk, or surf check. It's also a gorgeous spot to watch the sunset.
Close proximity to coffee shops and restaurants in Cardiff like Best Pizza and Brew, Lourdes Mexican Food, VG's Donut & Bakery and Rose Hill Purveyors also makes this trail perfect to grab some food/coffee and walk with a friend to one of the benches along the trail for a ocean-view picnic!
The Coastal Rail Trail can definitely be pretty busy, especially in peak summer/tourist times, but it's absolutely worth a visit.