Substellar science with the Euclid space telescope

Abstract: The wealth of data from the Euclid space telescope represents a major resource not only for cosmological studies but also for ultracool dwarf (UCD) science. Its Quick Data Release, covering 63 deg², has already revealed more than 5,000 UCD candidates. Over 10% of these have been spectroscopically confirmed, and more than half have available spectra showing characteristic UCD features. The sample spans spectral types from late M to late T. The first major data release (DR1), scheduled for October 2026, will cover an area 30 times larger, marking the transition of substellar science into the era of big data and enabling the establishment of robust photometric and spectroscopic standards. I will present the current UCD catalogue from the Q1 data release and future prospects with the Euclid data.