You can find dolphins anywhere in the world even the arctic and antarctic. Dolphins live in every ocean and even in some major rivers. Each place and ocean in the world has a specific dolphin that is native with that environment. For example the Pink dolphin lives in the Amazon River and the Atlantic spotted dolphin lives in the warm water of the tropics. Most dolphins migrate to where their food is and if there is an abundance they tend to stay local. Dolphins may travel up to 100 miles to follow their food supply.
Bottlenose dolphins are found in the Pacific Ocean from Northern Japan to Austrailia and from Southern California to Chile. They can also be found in the tropics of the eastern pacific and as far west as the Hawaiian Islands. They are also found in the Atlantic ocean from Nova Scotia to Patagonia and from Norway to South Africa and from Cape Cod to the Gulf of Mexico. Also the Mediterranean and Black Sea and from Australia to South Africa. This dolphin is the most common as you can probably tell.
Pink dolphins or Albino dolphins are very rare and were discovered in Brazil in the Amazon River. This is the only place in the world that the Albino dolphin are known to exist.