A swimming pool skimmer which has two independent pieces, a first piece and a second piece, fixed to one another orientably. The first piece forms a first guide tunnel for water in the swimming pool and has a first axis of symmetry in its longitudinal direction. The second piece has a body with a cylindrical wall and has a second axis of symmetry in its longitudinal direction. The first and second pieces are suitable for being fixed to one another in several possible angular positions in which the inclination, between the first and second axes at the level of the first and second pieces, varies from 90.degree. to 90.degree.+.alpha. max when the first axis, at the level of the first piece, has an inclination varying from the horizontal to an angle .alpha. max below the horizontal, the second axis being vertical.