An instant hose coupling, characterised by comprising: a body (1) comprising an axial duct provided internally with at least one O-ring (9); a male element (3) axially insertable into said body (1) so that a seal is formed between its outer surface and said O-ring (9); and at least two engagement members (12, 26) applied externally to said body (1) and each comprising an appendix (15, 29) which traverses a corresponding passage (11) provided in the body and engages in a circumferential groove provided in said male element (3) on the outside of the portion which seals against said O-ring (9).