Bacteriophages, or phages, are the most abundant biological entities on the planet and play a significant role in shaping bacterial populations within different environmental niches. In order to infect its host, a phage must first adsorb to a bacterial cell. This process may involve the initial reversible binding to a bacterial surface structure followed by irreversible recognition and attachment to a receptor by the phage’s receptor binding protein (RBP), triggering the injection of its genome into its host. We have isolated and characterised several phages that infect the important nosocomial pathogen Klebsiella pneumoniae. However, little is known as to how different phages recognise K. pneumoniae cells for infection. We utilised a functional genomics screen to identify essential genes, in terms of receptors, that are critical for phage infection of K. pneumoniae. These genes included the porin ompK36 and several other genes involved in the biosynthesis or secretion of CPS. We identified novel capsule hydrolases produced by these phages which act to degrade the bacterial capsule. Using in vitro assays, we have characterized the host range, activity and stability of one of these enzymes and have determined its structure using single particle Cryo-EM. Additionally, using a panel of engineered OmpK36 chimaeras, we have identified the critical epitopes of this protein which act as a secondary receptor for these phages. This work provides a greater understanding of the targeting mechanisms used by Klebsiella-targeting phages and provides a framework for their potential applications as therapeutics or use in the biotechnology industry.