In this paper we present Immersive Speculative Enactments (ISEs), a novel concept that extends conventional Speculative Enactments to Virtual Reality. Through ISEs, participants are immersed in a speculative world depicted by the designers and can engage with it in its truest envisioned form. We explore this concept via four scenarios with increasing technological uncertainty: a glimpse in the daily life of the parent of a newborn baby; a Mixed Reality experience supporting hybrid classrooms; two wearable devices that present a pet’s emotional state and needs; and an enactment on the effect of communication delay across interplanetary distances. We discuss the concept of ISEs and contrast them to other forms of speculation, provide guidelines on how to design them, as well as reflecting on the challenges, limitations, and potential associated with the role of ISEs in the HCI discourse.