Quick One Piece question.

[Captain_Action]

Is it ever explained HOW/WHY Luffy D. Monkey got into that barrel at the start of the show?

[B_real_shadows]

answer-NO
We do know however it was his only escape off of whatever boat he was on in order to survive the nearby whirlpool since he would sink and die otherwise and its basically just an interesting way to start the show off.

[Kima Azure]

So, technically, the answer is YES.

But it's, if I remember, MOSTLY mangá-mainly.