Use of 'wo' in "umi no naka wo oyogu yo"


> 海の中を泳ぐよ  
>  _umi no naka wo oyogu yo_

"wo" is the direct object particle, so does this mean "swim the in the sea?"
But that doesn't make much sense.

This was from a children's colouring sheet showing a character swimming
through the sea. Nothing else was written.




It actually means "swim through the sea!"(Exclamation added because the
sentence ends with yo.)

Some motion verbs use "wo" instead of "ni" despite being intransitive. See:
[Direct objects of motion verbs and help with the difference between を and
に](https://japanese.stackexchange.com/questions/61071/direct-objects-of-
motion-verbs-and-help-with-the-difference-between-%E3%82%92-and-%E3%81%AB)

