First off: Parking is easy on Ocean Blvd at 8:30 in the morning, a total plus in my book. There is the matter of a quite steep bit of stairs (about, three stories worth of stairs) leading from Ocean Blvd down to the beach, but if you were planning on swimming for an hour, this should not be an issue. If you really don't want to hike up and down those stairs, there is beach level parking at the state park for $15.00. Incidentally, this is also an excellent place to run as it is part of the OC Marathon course and there are some easy hills for hill practice.
The weather was beautiful, and the under half-mile long beach was populated by mostly other swimmers in wetsuits and a couple of people staking out prime spots for later in the day.
There are two rows of buoys lining the waters, the first set closest to the beach marks off the swim area, and the second row is to mark of the "no wake" area, so boats can (and do) come into the area between the two buoys to fish (and sometimes there are rowing boat team practice!) so you need to be aware of this if you want to swim around the second row of buoys.
There is a jetty and major rock formations around some parts of the beach, most of them are along the edge of the beach but there is the one that is right in the water directly outwards from the second lifeguard tower. You should obviously stay away from swimming anywhere near the rocks and jetty since the waves can get pretty aggressive depending on water conditions.
9am rolled around and the other swimmers of the meetup swam out to the first buoy and I joined them. Honestly I was kind of concerned about even swimming as far out as the first buoy. The group organizer asked everyone which route they wanted to take: The inside buoys or the outside buoys. I muttered something about just swimming in and out from the beach to the buoy but one of the "inside buoys" swimmers encouraged me to try to swim to the next inside buoy and that we'll take a break there, so I joined three other swimmers in the inside course.
Everyone on the inside course waited for the rest of the group to arrive before continuing to the next buoy. They were really nice about asking how I was doing and probably eyeballing me to see if I was starting to struggle. (I actually did not notice if there were lifeguards on the beach at that hour, though.) I had my reservations, but everything went better than expected and I was quite comfortable swimming through all the inside buoys and back to the beach. The 9am water conditions was quite calm. I did get knocked down by one wave standing around at the beginning, but once out closer to the buoys the water was quite calm. Water temps still required a wetsuit for me, but I was quite comfortable and knowing there were other people around (not necessary to rescue me, but to talk me through a trouble spot if needed) also helped me get over my mental hurdle of swimming through the waters. Overall, that was the longest continuous time I've been in the water without grabbing the wall or touching the bottom.
I was done in a half an hour, but the rest of the swimmers returned (after two laps of the outer buoys!) in just under an hour and quickly prepared for a bike ride (it is the OC Triathlete Training Meetup Group. Apparently there was a run before the swim, too!)
I would definitely recommend swimming with the OC Triathlete Training Meetup Group again! As for the Corona Del Mar State Park Beach, I would also recommend it for the easy parking (at least in the morning, parking gets a little more scarce after the morning hours and probably be even tougher in the Summer) and mostly moderate waves. Open waters can be calm to slightly rough (definitely rougher today when I went at 11:30am) but that's good practice, too. The beach is patrolled by lifeguards in tower 2 (center of beach) during certain hours, so you can check with them to get definite hours. Overall, this has moved to my number one swim spot for this season :3