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, phages use specialised tail machinery at the distal end of their tails to recognise specific features on the bacterial cell surface. 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 identified that our collection of Klebsiella-targeting phages exhibits specific host tropisms, such that the presence or absence of capsular polysaccharide is an essential factor in determining sensitivity to a given phage. We have subsequently characterised the interactions of these phages with their specific host receptors, detailing the cryo-EM structure and enzymatic function of different capsule degrading tail fibre proteins. Additionally, we have identified examples of mosaic tail fibre proteins which allow some of these phages to recognise alternative receptors on the bacterial cell surface. This work provides a greater understanding of the targeting mechanisms used by Klebsiella-targeting phages and a framework for the engineering of synthetic phages for more effective phage-based applications.