We were disappointed to find that the Biloxi beaches were less than ideal for swimming. The water was murky and the bottom felt more like a lake than an ocean with squishy muddy spots. Ship Island was completely different! The beach and ocean had wonderful, soft, clean sand. The water was warm and clear and perfect for swimming. We saw a variety of marine life including tons of dolphins that swam alongside the boat, and crabs, stingrays and small, harmless sharks at Ship Island. Definitely spend the $25 and rent the chairs and umbrella, it was well worth it. The staff was very attentive and informative answering all of our questions. Ship Island is part of the National Park System so our daughter was able to earn a Junior Ranger badge. We visited at the end of August, local kids were already back in school so there weren't many people around. All around we had a wonderful time.