The beach is both sandy and rocky in parts; there is a picnic area and pergola for eating a yummy lunch, playground for the kids, water fountains, and public restrooms. The off-leash dog area is open to you and your dog from November 1st to March 5th every year, but they can go to the beach at any time on-leash. Since this beach sits outside of Seattle, it tends to be a bit less crowded and there is plenty of parking in the big parking lot near the beach. The water is clear, but seaweed floats on the water and gets on the beach, so beware of this if your doggie likes to eat seaweed.
You should bring your own poop bags to clean up after your dog when they do their business. You will find trash cans in and near the bathrooms so you can discard the bags. Cleaning up after your dog is important for keeping to beach sanitary and beautiful. Bring your pup water to drink so they don't get dehydrated after running and playing on the beach and in the water. There are not many shady areas on the beach due to the lack of trees, so you may also want to bring an umbrella if it is a warm and sunny day when you go.
Overall, Richmond Beach Saltwater Park is a beautiful, quieter spot to take your dog for a beach day. The sand, water, and mountains in the background make for a peaceful and scenic place to spend your day!