Neutron triplet (3P2) superfluids are believed to realize in high density neutron matter such as the cores of neutron stars. I discuss topological aspects of neutron 3P2 superfluids such as integer vortices, half-quantized non-Abelian vortices and topological superfluidity. This talk is based on the work in collaboration with Kota Masuda and Takeshi Mizushima. | K. Masuda and MN, Phys.Rev. C93 (2016) 035804 [arXiv:1512.01946 [nucl-th]].| K. Masuda and MN,arXiv:1602.07050 [nucl-th] | T. Mizushima, K. Masuda and MN, in preparation.