The Open'er Festival (formerly as Heineken Open'er Festival from its principal sponsor, Heineken International) is a music festival which takes place on the North coast of Poland, in Gdynia. The first edition of the festival was organized in Warsaw in 2002 as Open Air Festival. The main organizer of the festival is the concert agency Alter Art. Open’er Festival was given the Best Major Festival prize at the European Festival Awards ceremony in 2009 and 2010. The 2015 edition of Open'er was held from 1 to 4 July 2015.
Since 2006, the festival takes place in Kosakowo Airport (Babie Doły Military Airport) in Gdynia.
There are three kinds of ticket available for sale: four-day tickets for the whole festival, three-day tickets (which do not entitle the holder to attend the opening day), and one-day tickets. As for previous Open'er performances, tickets are changed into wristbands at special points: one placed on the main train station in the center of Gdynia, and the other one right before the entrance to the Festival. Wristbands prove that the owner is a ticket holder and thus allow the festival's security guards to easily and conveniently ensure that individuals are entitled to attend the festival.