If you see the dolphin in a dream, then it shows the emotional state of your mind. There is a possibility that you are becoming better, wiser and more spiritual person. The dolphins are also known as very friendly animals, therefore the dream could indicate your wish to be surrounded by true friends. The dolphins could also signify how you are coping with your feelings, which means that you are going with the flow, without any stress. If you were riding the dolphin in a dream, then such dream shows the dominant aspects of you that are followed by your honest behavior with those you are surrounded by.
Read more about dreaming of Dolphins in other dream meanings interpretations.