I came to this area knowing about the limestone sinkholes for free diving under the river. Which disclaimer, should only be attempted by experienced divers very comfortable under the water. There's one main one that's good for average divers though people have died here so don't go trying things above your level as conditions change and blocked tube you won't get out of. You are going to however get an amazing paddle both directions up the river from the main rental site. Make sure you time your paddle to be at higher water levels so that you can make it into the beautiful underwater canyon. An underwater camera will really help you here. Easy camping, manatees and really enjoyed it and would go back.