Ocean health is fundamental to human prosperity. However, fisheries exploitation, industrialization and climate change imperil our oceans. Marine protected areas (MPAs) have been established in coastal habitats since the 1970s and the ongoing monitoring of these MPAs has shown their general ecological and economic value. Demonstrable benefits can include biodiversity conservation, fisheries enhancement and climate resilience. Since the 2000s, large scale MPAs (LSMPAs) are increasingly established, with new parks including extensive areas of pelagic habitat. Seminal was the British Indian Ocean Territory (BIOT) MPA created in 2010. In 2016, the United Kingdom Government established the Blue Belt Programme to provide long-term protection of the marine environment across the United Kingdom Overseas Territories and LSMPAs have now been established or designated in a number of these territories. However, empirical data for the Blue Belt LSMPAs are needed to test their effectiveness in conserving pelagic species and to allow managers to monitor and assess the LSMPAs based on the best available evidence. This Perspective presents current advances in video-based monitoring of pelagic wildlife and provides examples of key ecological insights gained from their use that are relevant to LSMPA planning and management. We present a case study from the BIOT MPA and finally generalize with respect to key learning’s that will support planning and monitoring of LSMPAs within the Blue Belt Programme.