Heavy neutral leptons (HNLs) are a common feature of beyond Standard Model (BSM) frameworks addressing the origin of neutrino masses. As an embedding of the type I and type II seesaw mechanisms, the left-right symmetric model (LRSM) emerges as an attractive BSM theory, featuring enlarged gauge, fermion and scalar sectors. In contrast to HNLs in the standard type I and type III seesaw mechanisms, the HNLs of the LRSM feature qualitatively different interactions with the Standard Model (SM) particles. I will discuss production mechanisms for HNLs of the LRSM at the LHC and FCC-ee, highlighting the differences to the standard scenarios and outline possible analysis strategies for their detection. In the long-lived regime, HNL production and displaced decay give access to probe left-right breaking scales in the deep multi-TeV regime, strongly surpassing direct search limits for the right-handed W_R.
