The female Common Kingfisher (only 3rd photo) is identical in appearance to the male except that her lower mandible is orange-red (in stead of black) with a black tip.

1st, 2nd & 3rd photo: Tam Coc, Ninh Binh, Vietnam, 9 January 2024
4th & 5th photo: Hoan Kiem Lake, Hanoi, Vietnam, 2 January 2024