True seals

Although they live primarily in an aquatic environment, seals return to land or ice floes for reproduction.

An excerpt from the article 18 facts about True seals
During pregnancy, females feed heavily in the waters, accumulating fat to avoid having to return to the water after giving birth. The accumulated fat reserves allow these animals to feed their young. The only exception here is the Harbor seal, which, after giving birth, returns to the water from time to time to feed - a trait common for eared seals.