We aim to describe our revision unilateral biportal endoscopic lumbar spine surgery (RUBELSS) approach, emphasising pre-operative planning, surgical technique, and management of complications. Key steps include utilising various endoscopic approaches based on the compression site, pre-operative magnetic resonance imaging (MRI) and radiograph analysis for surgical planning, and meticulous decompression with attention to anatomical landmarks. Additionally, potential complications like dural tears and intra-operative bleeding, as well as their bailout options, are discussed. Revision decompression for degenerative lumbar disease traditionally involves open or microscopic approaches. Endoscopic spine surgery (ESS) offers advantages over these approaches, including improved visualisation, reduced soft tissue disruption, and better short-term outcomes. Overall, RUBELSS presents a viable alternative for revision decompression, offering advantages over traditional techniques with superior short-term outcomes, faster operating times, and reduced complications.