Abstract Exposed to high fluxes of helium/hydrogen isotope particles and heat, tungsten divertor plates will suffer damage thus degrading its performance such as its thermal conductivity. This paper presents a study on the effect of bubbles on the lattice thermal conductivity of tungsten at the atomic level using molecular dynamics simulations. The present study finds that empty bubbles in tungsten lead to a decrease in the lattice thermal conductivity of tungsten. Furthermore, He/D filled bubbles aggravate this decrease. The physical origin of this behavior is discussed. It is also found that the decrease in lattice thermal conductivity depends strongly on both the impurity density in the bubbles and the bubble size.