Del Valle is one of the most beautiful lakes in the east bay. The water is perfect temperature. Great hikes, paddle boarding, kayaking, swimming and beginner windsurfing. The only cons are that you have to drive to go swim and the campground isn’t really walking distance to swimming. It’s pretty hot in the summer and it has a rocky ground so it will be hard to get stakes on the ground. It’s trully beautiful and the wildlife views are incredible. The water is super clear and they have two beaches with a lifeguard which can get crowded. You can swim at your own risk past the marina though if you want to bike, hike or boat to those beautiful areas.