Left: simulated observer-frame light-curve for a z = 2.0 SLSN-I in the four Euclid passbands. The horizontal (dashed) lines represent the assumed 5σ point source limiting magnitudes for each filter as discussed in the text. J and H limiting magnitudes are shifted of 0.05 and 0.10 mag to facilitate the reading. The cross symbols at the top of the panel represent a typical observing cadence for the southern EDS away from the six months gap (including two consecutive observations per passage that are not considered in the rate simulations), which would detect this SLSN four times in three bands. Similarly, the short lines at the top of the panel represent a typical observing cadence for the northern EDS, with four detections in three bands. Right: the same as the left panel but at z = 3.5. In this case both the southern and northern EDS would detect this SLSN three separate times (again excluding double observations within three days of each other). Observed phase is with respect to the observer frame J-band peak.