Do researchers need a separate work permit to carry out research in Slovenia?

For research activity covered by the hosting agreement, you do not need to obtain a separate work permit; the research permit itself authorises the research work described in the agreement.

The distinction matters if you want to do additional paid work beyond your research, or convert to standard employment. In that case the normal rules for non-EU workers apply and you would generally need a single residence and work permit. Keep your activities within the scope of the hosting agreement unless you have arranged the correct additional authorisation.