I think riding a horse on the beach is a romanticized notion that many people share. I have only gotten to do this once but I loved it. (Although I did wish I could gallop along the shore, which they did not let me do! Teehee) In San Diego, there are few beaches that allow horses. Fiesta Island, part of Mission Bay, does have the occasional rider. However, closer to the Mexican border, there is a place that offers San Diego Beach Rides. They offer several different trail rides and participate in a few off site events for pony rides and horse pulled wagon rides. I recommend this place to anyone! They have an odd little petting zoo of a farm and the people are very friendly. 🙂
P.S. The animals love treats! But ask the employees permission first!