We have swam with the dolphins twice at Discovery Cove. Its not a lengthy interaction (petting, kissing, "swimming"....where you hold their fin and they drag you a short distancce through the water).....about 30 minutes all told, in small groups of about 8 people (if your group is less than 8, you may be placed with another family). We have very much enjoyed it, but not just for the dolphin interaction: more for the entire Discovery Cove experience. DC is an amazing park and the dolphin interaction just enhances an already spectacular day.