NPI physicists participate at the large experiments like STAR - BNL, ALICE LHC - CERN, experiments at GSI and GANIL, neutrino experiment KATRIN. On the other hand, some NPI local experimental facilities are required and used by our foreign partners. Cyclotron U-120M serves for the measurement of astrophysically important nuclear reactions (collaboration Řež-Texas-Catania). Rather unique generator of fast neutrons installed at the cyclotron is used for the measurement of neutron activation cross sections required for perspective nuclear energetics among other (e.g. for projects IFMIF and ITER).

Neutron physics instruments at the reactor LVR-15 (the reactor operated by Nuclear Research Institute Řež plc) are used also by external users in the materials science and research. Experimental proposals can be supported in the frame of the Transnational Access Activity of the NMI3 project (Integrated Infrastructure Initiative for Neutron Scattering and Muon Spectroscopy, FP7).

A highly sensitive microprobe was recently installed at the Tandetron 4130 MC accelerator under substantial help from the collaboration with ATOMKI Debrecen.

There exist extended international collaborations in the most fields of NPI activities, like e.g. theoretical and mathematical physics, neutron physics, nuclear analytical methods, and radiation dosimetry.