Originally Posted by
elenaopen12
Just a heads up - staying overnight at HND (Haneda) can be a bit tricky. The airport actually closes between midnight and around 5am, and they'll usually ask passengers to leave the secure area.
I can confirm that HND T1 (Domestic) opens at 5am. On a recent trip, I showed up before 5am, doors were shut. Then I saw JL staff going in at 5am sharp, I went in with them. However, I did not know about T1.