Solo Day is the fifth mini-album released by B1A4 under WM Entertainment.

The album was released on July 14, 2014 by WM Entertainment and their distributing label Pony Canyon Korea.

There are 5 pictures: Jinyoung is "Couch Potato", Sandeul is "Pizza Delivery" Guy, CNU is "Obsession Guy", Baro is a "Space Geek" and Gongchan is a "Flower Vagabond".

has Baro trying to show Sandeul, Gongchan, Jinyoung, and CNU his headphones that make him look like an alien, the rest of B1A4 is focused on a UFO.

The official music video of Solo Day was released on July 14, 2014.