Billie Eilish had quite the day at the ballpark on Thursday ... she laughed, she snacked -- and then she turned the game into her own personal dance party!!!
The "Ocean Eyes" singer hit up the Dodgers vs. Giants game in L.A. with her family to celebrate the release of two new songs earlier in the afternoon ... and it ain't hard to see she had a blast at the stadium.
Wearing a Dodgers jersey (no name or number on the back), Eilish picked up a Cody Bellinger bobblehead, posed for pics with fans and enjoyed all the other sights, sounds and food at the venue.