How to explore the Sea of Storms in the Present Age?
Solution 1:
According to the article below, it is not possible to explore the Sea of Storms in the present unless you are in a Linked Game, due to this being part of a Password-Linked Event:
In a Linked Game, the Piratians appear in the present instead of the past, meaning the Sea of Storms is explored in the present as well, something that would not otherwise be possible.
https://zelda.gamepedia.com/Linked_Game#Oracle_of_Ages
Therefore, the entire map cannot be explored on the first play-through of Oracle of Ages.