A swimming pool is about your spiritual side. These dreams normally focus on specific spiritual abilities which are indicated by other symbols in the dream. The significance of the swimming pool is that it is a contained body of water with no outlet. The dream is asking you to remove any tendency you have to contain or limit your ability, and to create an outlet for it in your life.
Diving into a swimming pool, whether it is you or others in the dream, is a request to dive into life and / or your spiritual side.
