Can you get brain eating amoeba from swimming in the ocean?

The risk from seawater is almost zero. Naegleria fowleri does not live in saltwater. So swimming in oceans is considered safe. The problem is more with freshwater lakes, rivers, and ponds.

No, the amoeba cannot survive in salty conditions. Oceans have salt levels too high for it. That is why cases are always linked to freshwater.