Bethesda fully intends to bring DLC to Fallout 4, and they plan on releasing it early 2016.
Although we don’t know exactly what early 2016 is, or what the DLC will be about, we have some ideas on the latter.
At least, Fallout 4 fans who will accept any kind of hint they can get have some ideas. Early concept art had the main character looking out into the ocean, and a separate piece had the character on the bottom of the ocean.
While we are still unsure if the DLC will be have anything to do with the water, the speculation supports the theory of a underwater world thriving. We could also just be exploring the bottom of the ocean, which would be cool too.
Fallout 4 content will continue to release throughout the year, so don’t put the game away on the shelf yet.