do the waters of the atlantic & pacific oceans mix?

of course! All oceans mix, they are all connected to each other.

There are two places where the waters of the Atlantic and the Pacific mix. One is at Tierra del Fuego, at the southern tip of Argentina. The other is at the Panama Canal, which opened in 1913.

Both places are a problem, as creatures indigenous to either ocean move from one to the other, where they invade existing ecological niches with the potential to upset the balance of life. In the case of the canal, most creatures actually travel either attached to the hulls of ships, or in the ballast water inside ships moving through the canal.

The most recent example of creatures moving without human intervention is chinook salmon, a north Pacific species, which has been colonizing the coast of South America, and is now being observed in the Atlantic rivers of Argentina. The chinook is a fairly effective predator, so its appearance in the Atlantic isn't going to be good news for a lot of species, particularly penguins.

as others say Yes but the locations are more then 2 the southern most tip of South America the most Northern point of North America but just ever so lightly the Panama Canal also the Southern tip of Africa as the pacific mixes first with the India Ocean then the Atlantic