We present the discovery of 255 binary and 6 multiple system candidates with wide (>5arcsec) separation composed by ultracool dwarfs (UCDs) companions to stars, plus nine double ultracool dwarf systems. These systems were selected based on common distance criteria. About 90 per cent of the total sample has proper motions available and 73 per cent of the systems also satisfy a common proper motion criterion. The sample of ultracool candidates was taken from the Dark Energy Survey (DES) and the candidate stellar primaries are from Gaia DR2 and DES data. We compute chance alignment probabilities in order to assess the physical nature of each pair. We find that 174 candidate pairs with Gaia DR2 primaries and 81 pairs with a DES star as a primary have chance alignment probabilities <5 per cent. Only nine candidate systems composed of two UCDs were identified. The sample of candidate multiple systems is made up of five triple systems and one quadruple system. The majority of the UCDs found in binaries and multiples are of early L type and the typical wide binary fraction over the L spectral types is 2-4 per cent. Our sample of candidate wide binaries with UCDs as secondaries constitutes a substantial increase over the known number of such systems, which are very useful to constrain the formation and evolution of UCDs.

Cone search capability for table J/MNRAS/499/5302/table1 (The common distance pair candidates identified using the UCD combined to Gaia DR2 and DES DR1 data)

Cone search capability for table J/MNRAS/499/5302/table2 (The nine common distance pair candidates identified among the UCD and the letters A and B represent a different UCD)

Cone search capability for table J/MNRAS/499/5302/table3 (The common distance multiple systems found in our search)