It was very quiet when we were at Diani Campsite and Cottages only us and one other tent, we stayed 4 nights and had no problems. Good location 2 minutes from the beach, the campsite has fridges to use which is always a bonus, and seating areas which is nice, showers are fine, a basic campsite really.
The guys helped us put out tents up when we arrived and lent us mattresses and pillows.
There is not the highest level of security on the site, fences and gate aren't that high but the security guard at nighttime was so friendly and nice we never felt unsafe, and there is a safe to keep any valuables in.
The bar does good food, shows the football and there is a fruit shop 5 minutes walk up the road. We had a great few days laying on the beach!